Unauthorised debit orders

I have unauthorised debit orders going off my bank account with reference Luksha for R99.00. This has also been going on for over six months and have been reversing them. Last year in December I got ahold of their contact details on your website(HelloPeter). I phoned and informed them that I haven't signed up for any contracts with them, I gave my account details and they made a cash deposit into my account as refund and promised that they''d cancel. The debit orders are still going off my account. I'm loosing a lot of money as this is not the only unauthorised debit order going off my account.