Unsuccessful tracker service cancelation

I am a victim if abuse by tracker company. I was using them before and now I have another company cartracker that I am using. I tried to inform them over the email but their auto response informs that the email is wrong. I want to cancel but it seems that they do this to their customers. I tried to call them they referred me canceling department but there the phone rings forever with anyone answer. I am being abused. I don't want them anymore. Please help!!!