False DEBIT orders and upgrading with 0 consent

Mtn falsely upgraded a contract, we have been fighting with them for over a month. They have taken 2 false payments where the usual fee is 850 it has been increased to over 1200 rand. We have told them to cancel any upgrades or subscriptions and they cannot show us any evidence of us upgrading the contract. They also told us they would stop our debit order in the process and change it to cash which did not happen! This is theft, there was no authorization and the customer service has been awful!