To think boss shouldn't be doing this

[sounrealistic]

So I work in retail. Well known supermarket.
Opens at 7am tomorrow. I’m a supervisor and also a key holder so I can open up.

Probably once a month a supervisor who is meant to be opening up will call in sick the night before, or have family problems etc.
So this means the boss is calling me up at 10.15pm asking if I can work at 7am the next day.
I have preschooler children who I cannot find childcare for at 10.30pm at night.
I feel really pressurised and now I’m being asked what time I can come in, and what time I can contact my childminder.
I think boss wants to open up at 7am and then me to cover as soon as I can find somewhere for the kids to go.
It’s so bloody stressful.
I end up saying no to him all the time, but then I can passed up for overtime in the evenings that I could do, or any extra hours on my contract.
I am flexible and I can work most hours, providing I have childcare and I’m not being asked at stupid o clock at night.

It reads to me like the problem is that you haven’t actually said no. You’ve maybe said let me see about childcare, I’ll see what I can do.
As a manager myself in a similar environment I often need to find cover at short notice when people are sick. It is a job where you can’t just be without that person as they are needed to ensure smooth operations.
If I need to then I will contact team members and ask their availability. If someone says no sorry I have plans then that’s it and I will try someone else/ try to fix it some other way.
I can’t always cover it myself as a, I have my own children and childcare issues and b, if I did that I could easily work a lot of additional hours which I wouldn’t get paid overtime for and would severely impact on my work life balance.
If you aren’t available just make that clear. If your boss continues to harass you after that then it’s of course an issue and you must speak to them about it.

The only thing they're doing wrong is not disciplining the one always taking time off.

They need a supervisor, so they call others for cover. It seems as if OP says 'maybe', 'I'll try to find childcare', or doesn't respond so of course they're going to keep contacting for an update/more information. OP needs to give a firm NO or lay out how much notice she needs to be able to help.

I'd request a meeting with the manager/deputy and lay everything out. Also, get yourself in a union if you aren't already.

I use to work in a care home and was forever being asked to go in early, so extra or change shift. I found it so stressful, as like you felt like I should as they make you feel so bad. In the end o gave them my landline number only and changed mobile. When they rang house phone my step dad use to always tell them I was out 🤣 in the end I felt I could say a firm no and not be hassled further.
I would be straight and say with notice you may be able to help, but it's to short notice the night before when having children to sort. They can't punish you for not being able to cover unreliable staff...they should instead address the staff that call in sick.

why should people get supervisor positions when they can't perform all the functions of a supervisor

Being a supervisor doesn't mean you should be expected to drop everything and come into work with only a few hours notice

All supervisory roles I've ever had have been paid maybe a few pence an hour above the basic wage - they're not management level roles in that sense at all.

If they need more reliability they need to employ more people to have keys!

The supervisor who ended up going in early Today has young kids too.
So I feel it makes me look bad when I can’t drop everything to go in.
But she has got her retired, but still very capable mother living with her. So she can just disappear from the house at 6.30am and there will be someone there to take over from her.
I can’t magic up childcare at 10.30pm at night, especially for 7am the next day.
I’ve got my husband here, but his contracted hours are 7-4 Monday to Friday. Hence evenings are never a problem for me to do overtones.

Overtime!

Turn your phone off

So speak up!

Tell them in writing that a) due to your circumstances you can only be available for work with x hours notice and b) your contract doesn't cover emergency cover.

Also - is today actually a "day off" as in you should be working but have booked it as annual leave? If it is then it's a day off but if it's not then it's a non-working day and should be referred to as such. It's a little tweak with the language but it makes a big difference as to how people react.

For example, my contracted days are Tue/Wed/Thu this does not mean that Mon and Fri are my days off. It means they are my non-working days.

It’s not my contracted day today.
So it’s a day off.

Then say no. FFS!

Honestly OP, as someone who has been on both sides of this, I can understand the not wanting to say no and the guilt. BUT from the manager side, the people who say 'maybe' or 'I'll try' without meaning it are more hassle than the people who outright say no. With a firm No I can start calling other stores for cover or try my area manager to see if they can help or even provide proof that the LTS person needs to be covered as it's causing too many issues. With a firm No, I was instantly aware that I was doing more overtime and start planning for that, with a maybe, I was left not knowing if I would be getting up early for a shift. By being wishy washy you are causing more problems.

Tell them that you cannot work early mornings without notice. Maybe then they could call the PM supervisor and ask them to do the morning shift with you doing the PM shift.

Seriously OP how much roughly do you earn? Probably not enough to make this worth the hassle. There is clearly a reason the other supervisor is on long term sick if this is how staff are treated. You are better than this!

I used to work in a supermarket and they were very stingey about hours. They'd realise there wasn't enough staff in and would call me last minute to come in. Didn't matter if it was my first day off in 10 days, they'd still ask me to come in. Drove me mad!

However you can say no, if it's not your contracted day/hours you don't have to go in. You have children to look after and surely they have other key holders? If you work in a large store you could speak to HR about this as he shouldn't be putting pressure on you to work at such short notice.
Or if it's a small store without HR then is there an assistant manager you can speak to? But surely they should be dealing with colleague for consistently calling in sick? At the supermarket I worked in after 3 times of calling in sick in a year you'd get a disciplinary (which in my opinion was ridiculous)

Has the other supervisor actually said that they're unhappy to be called in? Could you go to management together to express your concerns? She's also probably contacting you so she has some idea of when she'll be finishing, what breaks she'll be getting, how to organise work. Being uncertain about a finish time is much worse that knowing that you're working for a full shift.

Is the manager doing anything about the supervisor who is constantly off? If the manager isn't doing their job and dealing with it maybe them having to always cover will concentrate their mind and get them to deal with the problem supervisor.

@sounrealistic that's not a day off. It's never been a contracted working day so by default it can't be a day off. It's a non-working day.

I like Pp suggestion of saying childminder insists on minimum 12 hours notice for additional hours.

Well, quick update. I messaged manager this morning to say I appreciate the offer of extra hours, but I couldn’t get childcare at this late notice.
I got a one word reply “right”.
They know how to make you feel guilty.

Urgh that's disgraceful. Don't feel guilty, you haven't done anything wrong.

dont use childcare as your excuse op

@sounrealistic - It's hindsight now but a better message to have sent was "I appreciate the offer of extra hours but today is my day off and I'm currently unavailable to come in".
Whatever makes you unavailable is not their business and they really don't care what you get up to when you're not in work but you have to assert yourself. They clearly have no issues with contacting you on such short notice asking you to work on your day off, so you shouldn't feel any guilt in turning that down.

In relation to your AIBU question - no you're not BU, they are.
You could approach your manager when you're next in work and ask for a quick chat to set up something on a more formalized basis when it comes to sorting out cover at very short notice. You should get at least 24 hrs notice if someone isn't able to come in (if that is feasible and workable). No to coming in on your day off etc. etc. etc.

OP, they can't make you feel anything.

Once you become aware of that, the world gets easier.

They wouldn't think twice about fucking you over. It is a business relationship, try not to let emotions come into it.

Honestly OP in my experience supervisory roles are rarely worth it unless you have a clear timeframe to escape them!

I've done it twice and the pay and hours were absolutely shit when you look at all the added responsibility.

When I was supervisor I was on £50 a month more than basic wage - absolutely not worth it long-term considering I often had the responsibility of the shop manager who was earning 7k a year more than me!