Cartrack hell experience and unsatisfying customers

Cartrack is coning me,I was not happy with their service but I hanged in there to finish my 3years contract withh them which it ended in 1st June and they took a debit order from my account on 25th of June of which I reversed and they started calling saying I am in arrears as I need to cancel the matured contract more over I was over charged as I was paying 187.00 instead of 154 rands,now they say if I cancel the contract now they will still deduct funds from my account for june and july as it stand I am apparently liable for 500 plus Rands I don't even know how it got to that funds and when I call in I get *********** consultants that cnt even explain to me of whats happening.