Not been paid, again, maternity related

[Squeezed]

Hr and payroll are outsourced and they haven't paid me. I notified my manager of return to work dates after maternity leave and requested kit day payments well in advance of pay cut off date. Chased up manager when hr said it wasn't done, then chased up hr who confirmed it was all done and I would be paid. Now I've not been paid and I'm told by hr that both types of payment missed the cut off date. This can't be my error as I don't need to submit forms, just inform my manager. There were similar problems last month that haven't been resolved and it has cost me a lot of money in phonecalls.
I'm going into work with baby tomorrow because telephone and email hasn't worked. I'd really appreciate any advice on how to handle this as I've been so stressed about it since I received the email saying they weren't paying me.

[Mu123]

Did you get things resolved squeezed

[TheDrunkenBotanist]

Are you def sure 're kit days and forms? I had to then got paid 2 in lieu- I'll get paid for Feb kit days in April!

[Squeezed]

Still not resolved. Even worse as hr have come up with a daily rate for KIT and annual leave that's approx half pay. I've definitely done what I needed to. Just needed to inform line manager, I've done this verbally and in email. I also chased it with HR (a lot) and then chased up manager. Kit days go all the way back to December. Hr told me it would be paid this month but now they're saying it'll be next month.
Manager has been quite good at chasing I think. I've had a random payment that's a fraction of what I'm owed and I don't know what it's for. I'm supposed to have a resolution today, but it's now a week since payday. It's does seem to be a combination of incompetence and treating me unfairly with me being on maternity leave.
I'm just at a loss of what to do, I'm stressed and angry. I cant easily ring them with two children at home and it is costing me a fortune to call from home.

[redexpat]

Are you a member of a union? If not can you call acas?

[Squeezed]

Acas have given me some options, unfortunately all of which will take time. Same with union. Grievance and giving them notice to pay still takes a while to get anywhere. My manager hadn't heard from them this morning so it will be escalated, but that doesn't help me now.