Tracker its the *******

I had the tracker for last 2.5years I bought another car so I ask tracker to guys to remove the tracker they said I don't have to remove the tracker ,but they going to deactivate the old one, on 27th of December 2015 R595 was debited to my account ,this month 2 February 2016 another R494,was debited on my account again ,I phone the lady I asked to speak with supervisor ,she make me hold for 20mins,I hand up ,I phone the again this time guys with bad attitude explain about pro rata ,I ask why pro rata he said because you join the new contract that one is deactivated, I ask him so we not allowed to change cars because we have tracker contract he said you are but the contract started again ,so my question we not actually going own this tracker because every time you change car new contract start again, TRACKER IS REALLY *******