Demanding for fees to the room I didn't occupied:

I need legal advice regarding a tenancy agreement I signed with Apollo Works. Here’s my situation:
I arrived in the UK on October 4, 2024, and booked student accommodation through Homes for Students on October 5, 2024.
At the time of signing, I was unaware of UK tenancy laws and did not fully understand the implications of the contract.
I never received the keys, never moved in, and never used the accommodation.
The accommodation required a guarantor, which I did not fully understand as a newcomer to the UK.
I chose the alternative payment option, but I later found out that the payment had to be made in one full stage instead of installments, which was a misunderstanding on my part. Had I known about the guarantor requirement, I would have been able to choose a monthly or quarterly payment plan.
Due to urgent housing needs and extreme cold weather, I was in a desperate situation and signed the contract without full awareness of my rights and obligations.
The contract included a 72-hour cooling-off period, but I mistakenly sent my cancellation request three weeks later, due to my lack of understanding of UK laws.
Despite my non-occupancy, I am being pursued for a balance of £4,330.58.
On January 6, 2025, my booked room was occupied by another tenant without my consent or notification.
I believe this violates consumer protection laws, as I received no service or benefit from the contract.
As an international student, I am financially unable to pay this amount and seek legal guidance on whether this contract is enforceable, and if I can dispute these charges.
Please help me in this regard. I would greatly appreciate your assistance in resolving this matter.