24mnths contract not terminated by Telkom

I signed a Telkom 24months contract in March 2019, it was 2cellphones and 2simcards with different numbers. and I have been paying monthly debits religiously.. According to my calculations the contract was supposed to be terminated by end of April. Surprisingly my bank account has been debited for the months of March, April, May, June, and I just received an invoice saying R220. 00 will be debited on the 31st August 2021. I'm so angry because I have not been getting any of the benefits from Telkom yet they keep on debiting my account. The cell numbers have been converted into prepaid numbers. Why am I being charged for service I don't receive from Telkom???