Showmax double billing me for one active account

Showmax has been incorrectly debiting my account for the past xx months while I was making prepaid payments because their system was not accepting my EFT payments. A day after I make prepaid payments, they would debit my account and from Jan I’ve been paying them via DSTV and they are still debiting me. I have been making payments month to month because my subscriptions would expire monthly and I was prompted to make re subscribe to continue watching. I only have one active account with Showmax at the moment and it seems I have been double billed. I want my refund ASAP