Help! My uni is trying to charge me a whole year of fees despite withdrawing

Hi all, honestly don't know where to post this just looking for any general advice.
To keep it short and brief I unfortunately had to leave a HE access course end of last year (2022) due to compelling personal circumstances, which involved 2 bereavements and serious health/medical things I of course supplied evidence to my uni and my personal tutors were aware of my circumstances. So I left, hoping to resume at a further date when I had recovered and medical issues resolved. I also had an ongoing medical diagnosis that was not finalised at the time that was a big contribution to leaving.

Out of the blue today (May 2023) I get an email with an invoice for a large amount of money with 14 days to pay (threatening adding interest if I don't pay) and my uni are now attempting to charge me for a full year of tuition out of pocket even though I have not attended any lessons and had all my stuff withdrawn and access revoked start of 2023 and handed all my stuff back. I can't find any written evidence in any of my official paperwork or learning agreement I signed that says in writing I am liable for full tuition fees if I leave the course, and I especially think this is wrong considering I had to leave due to personal circumstances totally out of my control. The uni have my medical evidence and doctors notes and from previous experience this is not something a university usually tries to do. The small part of the course I did complete was already paid for by an advanced learner loan from student finance. My uni are asking me to pay the remaining amount that would equal a whole years tuition out of pocket, even though I withdrew months ago!!

I've asked them to provide evidence in writing and documents showing where it says in university documents I am liable to pay these fees and so far I haven't received anything from them. I have reviewed my own copies and I can't find anything in writing that says I have to pay. The communciation is really sporadic and sometimes their replies have taken over a month and I keep getting passed around people and told different things depending who I talk to. I've had to get my parents involved and it's turning into a complete nightmare!

Has anyone else had a similar situation? Would love any advice and thoughts whilst trying to get this sorted