Poor service and double debit

<div>Cartrack double-debited my account. I was redirected from client services to accounts and then back to client services. I inquired about the amounts of R163 debited on the 3rd and R149 debited on the 6th of the month. I've been told that R163 was made up of a fee of R19 and a pro-rata subscription fee. My question was, why must I pay again for the same month, a few days later? That constitutes a double debit for the same service. The answer was that they cannot help it, that is the cartrack policy. Is this LEGAL?</div>