unauthorized debit order

These people through a debit order that was not authorized by me took R169 out of my account. Told me over the phone I have authorized it but I never received any such sms or request. Now I have to send email together with my bank statement to proof that it was them who received the debit order for a refund as the cannot do a reversal on the debit order. I refuse to allow them to ***** my money for absolutely nothing in return.