Cellphone Insurance (Refusal of Cancellation)

I currently have a telkom contract for S8 phone which is ending early next year so I decided two months back to rather cancel my insurance on the device which I'm being charged R198 per month. Instead of the cancellation being cancelled immediately I'm still getting billed for insurance which I really do not need each and every month. I've called the call centers but still no resolutions to date. Telkom makes it extremely difficult for clients to cancel anything and I can't wait for my cellphone contract to end so I can never deal with such bad customer services ever again.