Unauthorised debits to my cheque account

I have been trying to have Greenbacks charhes rrversed since July 2022, I have case no's which I have sent to them vis email. There are also numerous unauthorised debits which went off in Oct . I have been trying to contact the call centre to no avail. I sent an email explaining that the funds were to cover my medical aid for Nov. These chearges has left me with a negative balance, and not enough to pay my medical aid.