Cell C - unauthorised debits and extremely bad service

I settled my account in full on 8 Jan 2020 (paid R3831.25) and handed proof to the consultant at Walmer Park PE who proceeded to cancel my contract. However, on 31 Jan Cell C debited me with R335 and then with R3496.25 on 29 Febr 2020. Trying to dispute this is an absolute nightmare. So frustrating trying to get them to link the payments and refund the 2 debits!! What do I do? Capitec cannot reverse the payments as Cell C was suppose to have cancelled the debit orders? How do I get my money back???