What can happen to me?

I know i am not right i what i have done. i have a vehical that i stopped paying on in dec 2007. i talked to the bank at first and asked if they could work with me and reduce the payment, they said no way. then after afew months i called them and asked them where they wanted me to take the car, i wanted to do a turn it in. they would not work with me on that. they wanted to hire someone to repo it from me. they kept calling and calling all hours of the day. i became fed up with there harassing ways and put the car in the back yard. and never answered there calls again. now its oct 2009. i still have the car and they don't call or send letters and my credit report says they charged it off. so what can happen now. i don't like it this way but i gess i need to do something