Garage Rental

Hello,I used to rent a garage and they raised the rent so I called the office and told them that i couldnt afford the rent nomore in 09/08.Then I recieved a phone call and then was told that i owed them 400.00 12/08.even after i told them i didnt want the garage anymore.they said that they mailed me statements but to my old address,They also have my phone number and never recieved a call from them untill 12/08.I tried speaking with them but they just keep telling me i owed them 400.00 and that all they was saying.What should i do? - Is this your question? Add additional information