We buy cars are ******

I bought a car from we buy cars and they did not tell me about its problems so now they are telling me that I signed terms and conditions..when it's raining the roof becomes wet and my mats are starting to stink..I am not happy at with we buy cars..can somebody please help me J am desperate..I also found out the car was actually white and not grey..I think they ****** me and I want my money back..the paint is coming off and under the paint there a cracks that shows that the car was on an accident pls help me