Direct TV extended my contract without notice. refuses to cancel , Internet

I went to Best Buy and bought a HD box to replace a standard box. I already had HD service. Last summer after losing my job, I called and asked them to cancel my account. It was then that they informed me I still had time left on my contract.

I had already been with them for 4 years and told them I was past my contract. They said since I bought the HD box, I had extended the contract.

No where in Best Buy or when I called Direct TV to activate the HD box did anyone tell me I was extending my contract. I have gone through the reciepts I got at Best Buy and there is nothing there. I would not have bought the box had I known they would do this. I already had HD on my main tv.

These guys suck!