DStv stole money out of my account.

I cancelled my DSTV over a year ago. This month they debited my account out of the blue. They say a "system glitch" activated my account and the debit order was processed. I have called them three times and they have promised a refund. My last call was on Tuesday 12 May. I was told my refund would take 48hrs. I have not received the refund. I don't know how to get the money back that they have ******. Especially at this time where my household income is affected by COVID-19 I cannot afford to have large corporations taking money out of my account ********ly. I don't know what else to do other than open a case of theft with the SAPS.