Just moved in a dirty flat. Rent paid in advance. Please help me.

I think I did a big mistake..

I was living in Scotland and decided to move in to Plymouth.
I've found a furnished room in a shared flat on internet so I got in touch with the agency responsible for it.

I wasn't able to come over for the viewing with this Covid situation so I had a viewing video instead. The flat looked lovely. As I didn’t have a job in Brighton yet and no UK guarantor I had to pay 6 months in advance.

I've moved in today and we did a quick check-in as the letting agent seemed to be in a hurry.
She showed me my room where I noticed that the window was in a really bad condition. Impossible to open it and air coming through. She told me that it was going to be changed asap. She told me I could contact her if I had any questions and she’ll send me the inventory soon then she left.

After she left I did a deeper tour.
My room wasn’t clean: hair on the floor / in bedside table drawers.
I’ve opened the kitchen cupboards and found only 2 old dirty looking wine glasses.
Nothing else. No mugs no plates. And only 3 pans for cooking.
 I opened my fridge and found that the freezer part was sealed and not accessible + fridge not cleaned.
The window in the kitchen cannot be opened. The extractor cooker is completely sealed with dirt as well.
There’s mold on the walls.
The quality of the flat is literally rubbish… And I imagine that the letting agent was well aware of that and just avoided showing me all this during the online viewing.

I’ve talked with my flatmate and she told me that the agency were supposed to fix the kitchen window long time ago but never did. The flat has apparently always been dirty. When she arrived she had to buy glasses, plates and mugs.
The wifi is included but barely works as it is shared with other flats within the building.

I’ve sent an email to the letting agent but no answers. However she was really efficient with answering when we were talking about paying the rent.

I’ve paid 6 months in advance so 3600£ (all my savings) and I cannot stay in a flat like this… I feel really really bad and I’m alone in a new city 
What can I do? I really need help..

Thank you so much for your time....

This took me back to grotty flats I lived in back in the mists of time.Heavily pregnant I was trying to clean the filthy kitchen,leaving the oven to the end.I opened it up to find a squirming mass of maggots on a half-cooked leg of pork.The previous tenant had obviously left in a hurry.When I went to put money in the electric meter there was a dead rat on top of it.
Obviously things like the broken windows can't be easily mended,and you have every reason to feel you have been fooled.However,you can do something about dirt and hygiene without spending much money.It is very rare for tenants to not own basics like crockery and utensils.
It sounds as if the move was done without any thought of the consequences,when you were feeling very low in yourself? That is a lovely part of the world you have moved to,lockdown will end soon and you will find work.Try not to panic,if you move back to Scotland you will have the same problems that caused you to leave in the first place. The Samaritans are always available to talk to,and walking by the sea can be very healing. Getting your personal space clean and sweet -smelling will be a good start.Hang on in there!