Unapproved debit orders and no refund given

My usual monthly debit order came off as usual, then the next day an additional R150 was debited. No explanation. No advance notice. I have tried communicating via WhatsApp but I can't seem to get any actual information out of their staff. The first person to handle my query just said that my money would be refunded. It has not been refunded. The next person asked for my proof of payment. I did NOT PAY YOU, YOU TOOK IT FROM ME. I cannot seem to get them to understand that this was not communicated or explained what this extra debit was for or why it happened. I cannot get an explanation or a refund. Terrible service. Terrible system that randomly debits people random amounts and staff cannot explain why or refund my money but instead ask me for proof of payment for a debit orders I did not approve or make myself. They just took my money from me and refuse to give it back.