Worst customer service from MTN

I am having the worst terrible treatment from MTN. They are the worst when it comes to customer service. In fact they are **********. I had a cellphone contract with MTN which ended on 26/08/2020. In July MTN started debiting my account more than the normal amount. When i went to inquire at their Welkom Store i was told that i had upgraded my contract to include unlimited calls and sms. I told them i never upgraded my contract and demanded to see the contract i allegedly signed or them to release the voice recordings where i authorized such an upgrade/contract. They have not been able to provide me with such proof, instead keep debiting my account for not less than R4,000. This month they debited R5,625. When i call their customer service i keep being sent from pillar to poster with the matter not being resolved. I am having no luck at their store either. Can i be protected from these **********.