no service

I bought a new vehicle more than a year ago and requested Cartrack to switch the tracking unit to the new vehicle. After a year still not done but every month receiving the bill which I later refused to pay. It doesn't help talking to them when they call you , no response on emails I sent to them. (Return NOT DELIVERED TO BOTH ADDRESSES). Now threatens to blacklist me. The best service!!! One star actually too high. If you blacklist me, I'm sure there will be a sue case