So am I the one in the wrong here?

The students can refuse permission for you to do this though. You might do it as standard, but if they specifically request you don’t, you have to agree.

I've worked in sixth form education for 15 years across both school and college settings. Some students stay on a third year so attend until 19. They're treated exactly the same as under 18 year olds, and because they're no longer funded by the government we're essentially doing them a favour and managing a tighter budget to accommodate them in the extra year. Therefore if they don't meet our expectations, parents are still contacted. Likewise, those in second year of sixth form are still held to the same standards once they turn 18 and parents continue to be contacted as normal, regardless of them being legal adults.

Not relevant to the original post, but you seemed to be questioning the OP's version of events, which is perfectly reasonable.

Start with no food in bedrooms, and work up from there. And throw her out of her room every day for an hour to do her room, preferably at 6:00am, 'if you can't do it yourself, I will have to'.

Also me and the 19 year old do have a rocky relationship (due to years of parental alienation from her dad) and he caused a lot of issues

Can you explain this a bit more?
Has she only recently come to live with you?

I asked her to go out with her dad today with my other kids as I just wanted to be in this house alone and not have to worry about dealing with her she's refused to go

This is awful.
You cannot ask your child to leave their own home for the day because you can’t be bothered ‘dealing with her’.

That’s awful and I would never say that to my child.
It’s no wonder why you two have issues.

If you want time alone then go into your bedroom.

Obviously her having rubbish in her room is not good.
My DD is similar and I regularly tell her to tidy it.
I brought a bin for her room and I then replace the bin bag when it’s full.
I told her that I’m not cleaning her room but she can ask for my help and although it’s not perfect she does ask me to help her now when she gets overwhelmed and then for the next few days it stays a bit tidier.
Its not perfect but it’s getting better.

I assume there’s no way your DDs can have their own rooms?

I feel really sorry for the 18yo in this but I would provide a bin which I would empty regularly and then leave it up to DD.
Tell her to put the rubbish in the bin and if she doesn’t then it’s on her.

You need to pick your battles and if she wants to live in a pig sty then so be it.
Tell her if she makes an effort to put rubbish in the bin, then she can ask for your help if it gets too much.

Just the process of asking for help and you doing it will help towards strengthening your relationship.

Obviously there are much bigger issues here and these need to be dealt with more than the rubbish in the room.

Please exhaust any other ideas first. My mother did this to me at 17 and I cut contact that day and never went back.

So she does leave the house.
And presumably isn’t a complete skank if she has a boyfriend?

This all sounds like a huge cry for help to me.
6 bags a fortnight?! What is going on up there?

Does she talk to her sister? Have you tried talking to her?

Tbh, you sound a bit knee jerk about these issues rather than a parent. What’s going on with her?

I find the lack of WiFi is good for motivation..

That must be very frustrating for you, but the parental alienation was not her fault.

It sounds like you need to invest in rebuilding the relationship. The other stuff probably won't be resolved if your relationship doesn't improve.

Can she go and live with her Dad?

Talk to her. Tell her you will not tolerate the mess in her bedroom nor her disgusting attitude towards you. Give her 4 weeks notice to improve, then she’s evicted. She’s an adult. She should start behaving like one.

Well at 19 she is old enough to find her own place to live.

She’s an adult now. Clean up or ship out.

Wheres she getting the money from to accumulate all this rubbish?
And is she not leaving the house to buy it?

Her behaviour is terrible. She should get rid of her own rubbish (with the 18yo doing their fair share), she should do her own washingb up and she should stop swearing at you.

But I suspect that there is more to it than this. Why are you so eager to get her out of the house, and what does that have to do with anything. What is the quality of your relationship like more generally?

I have a 19yo and she wouldn't dream of behaving like this, but that's because we have a healthy, mutually respectful relationship. What's gone wrong between you and your dd that means you don't have that kind of relationship?

Just chuck her out. I couldn’t be arsed with this at all. I’ve got an eighteen year old and a twenty one year old and if one of them told me to shut the fuck up id have their guts for garters.

So when and why did this start happening? Because none of it sounds normal.
Skips college
failing course
Sits in room all day
Eats in room
leaves dirty dishes around room for days
generates weird amounts of "rubbish"

She didn't just wake up like this one day, she sounds like something is going on with her, has something bad happened at college? Is she maybe depressed?
Have you tried to talk to her about why this is happening? You sound very resentful, and I can see why, but nagging at her and telling her she has to go out of her own house so you can be on your own isn't helping.

I'm confused, who is the 18 year old and what is their relationship to the 18 year old? Sibling? Partner?

I'm surprised the college have been asking you to attend meetings at her age. Does she have additional needs?

Those saying kick her out, would you honestly see your 19 year old homeless and living on the street? People talk a big game on here but it's hard to believe many would go through with it.

Do you have a DH/DP? If so can you talk to your DD together. If she's not going to attend college then she needs to get a job.

“If I’m to shut the fuck up - you can pack the fuck up and ship the fuck out you skanky cow- your choice but you have an hour to think about it- brew?”

I’m confused as to who the 18 year old is, and why college is speaking to you about your adult daughter.

But regardless of that, time for some tough love. It sounds like she’s crying out for some boundaries!

How is it NOT an issue. What a bizarre response

I think it's time you sat down with her and established some ground rules. She sounds very unhappy but that's no reason to disrespect the family home

Ban food and drinks upstairs for a start.