Tracker and their ************ ways. Taking money from my account for a unit they never installed.

Tracker keeps taking money from my account for a unit they never installed. I bought my car with a unit installed from the dealer and this is the third time I have to call and complain about this. I called thei customer service after received a sms about money that will be deducted and I queried and asked why but they couldn’t give me a clear answer. They making this a difficult Relationship ship and after this I’m canceling them. I need my refund asap.