Not getting refund for extra subscription deducted

Multichoice deducted my premium twice in June. I have been struggling for a month and a half to get my money back. The call centre keeps promising to escalate my query to 'central finance' and then send me the most ridiculous answers as if they've resolved my query. We heard from other people that double payments happen to them regularly as well. I am fed up with the call centre and seriously consider cancelling my subscription if I don't get a reasonable answer soon.