Accommodation fee query

Thurrafork

Hello folks
Asking on behalf of a friend...
My friend from Taiwan is at university in London studying for her PHD.
She was due to be returning to Taiwan in May to continue her studies there, but obviously things have gone a bit crazy with travel restrictions/costs etc.
So she's kind of stuck in her dorm room paying expensive accommodation fees.
When lockdown started 3 weeks free accommodation was offered to all the students - very nice. But of course after that she has been paying.
A few weeks ago she asked to extend her stay until 31st July. The accommodation office said Yes, they stated the fee to cover accommodation until that date, my friend agreed the amount and paid it. Done.
But now, about 3 weeks later, they have suddenly got in touch to say they made an error and that the amount they requested was £36 short.
So they say she must either pay the £36 or they will deduct it from her deposit.
I know it's not a huge amount of money, but it just seems a bit rubbish!
What are my friend's rights here? Is this a circumstance where she can say she agreed the amount they stated and paid it - and that's the end of it? This is their error, so they must honour the original quoted amount?
What do you think?
Thanks!

silvercar

It’s £36. She could write a letter, instigate a complaint following their complaint procedure.

little point going to court for that amount.

Thurrafork

Thanks for the reply, silvercar.
Yes, of course if the process is going to be that involved then it is not worth it.
I just wondered if this was something that could be easily refused.
Like that whole notion that if you buy something in a supermarket and it is mispriced, they can not subsequently ask you to pay the difference. The error is theirs and the price originally stated is something they must honour.
Is that a thing?
If it is, I thought the same principle might apply here.