Vodacom Contract

My contract with Vodacom expired in January 20202 and i have been trying to cancel it for the past 7 months, every time i call they will tell me that the account is cancelled, month end they deduct more money than the actual contract amount. Now they have blocked my number, i cant call in to make follow up. I sent emails on their customer care no one reply. I have learned that they upgraded my number to another plan without my consent