UK Landlord Forum / Life

I need advice please.
At the start of February I moved in to a new flat share. The deal was £400 deposit and £440, all bills included, rental for the room up from each month. This was paid and set up as standing order from my bank. There is no written contract and the landlords agent lives in the house. Basically one house mate takes charge of the rent and bills and we all pay into her account as per standing order mentioned above.
A short time in to the rental a few difficulties arose. Heating was monitored to safe costs. I was accused of using excessive gas, although as I type this I am sitting in the living room wearing a coat and hat to stay warm.  The heater controller was changed and I have not been informed how to use it to get the heater on. Heating is under agent's control.  The shower unit rarely works although the official landlord did make changes and repairs since the new controller was fitted it became impossible to have hot water for a shower as I did not know how it was controlled.
The current flatmates and me are very different characters and I understand that moving into a house can create personality differences but that is not the overall issue here. On the day I moved in the front door key would not work without huge force and effort to open and lock the door. I was accused of banging doors...okay maybe I did maybe I did not.
I was asked by the other flatmates to attend a hose meeting. During this they said things were not working out and gave me one month to leave. I did not care as I was unhappy too. I cancelled all standing orders the next day.  A friend stepped in and offered me a room until I get back on my feet and I am anxious to get out of here. I told the agent and asked for my deposit back when I lave on Saturday. She said no, I will have to wait until a new tenant takes the room and I can have his/her bond once it is taken in a month. I offered to meet half way - give me £200 when I lave and the balance when the room is taken or within one month. She refused.
Where do I stand? I am considering keeping the keys until I get paid but understand that this might mean I still own the room. A s far as I am concerned she ended the agreement and I needed to act fast to get out of a very uncomfortable situation. I also feel she breached any deal otherwise as the is not heating or hot water here - I have showered at work all this week.
How do I get it all back when I leave on Saturday or at least be certain she wont keep it...
Thanks in advance for any help
Sean