Cancellation difficulties with Telkom

I wrote a letter to Telkom in November 2019 to cancel my some of my services but they never did . I send another email on the 26th of May and I was told it should be out by end of June. End of June came I was still billed for it and the services weren’t cancelled . Am not sure what to do because I need to cancel the service and can’t keep paying for services that I don’t need. May it would be good idea not to take a contract with them if it’s difficult to cancel.