I am furious with Vodacom not wanting to terminate my expired contracts.

I am really not happy with Vodacom. I feel that they are taking advantage of the lockdown situation. I have 2 contracts with them that expired and asked them too many times to convert them to pre-paid. I even wrote them a letter. I talk to their contact center agents, they still don't terminate the contracts, they keep on billing me monthly. Vodacom please terminate my expired contracts, you sending me bills is messing up my credit record because i will not pay you anymore for services i am no longer using.