Deductions continues after cancelling my service

After struggling to get my corporate discount app**** to my account since inception and trying to get a refund of the overpayment for the last 4 months, (which I'm still waiting to be resolved and after being promised multiple times that it will be paid back to me) I decided to cancel my subscription with Supersonic. Since the cancellation, they have been deducting the monthly subscription TWICE now already.

I really hoped that it would be the end of the road with them, but I was wrong. How difficult is it really to cancel the debit order? I don't know what else to do. The same answer you get every time is that they will send a follow up to the relevant department. Nobody ever gets back to you and nobody ever resolves your problem. I'm really at my wits end here.