What does it take to cancel contract

I called VA around December 2019 to cancel my month to month contract and thought that all was in place. I never head from them until earlier 2021 when they call to inform me that I haven’t paid my monthly payment and I explained that I had already cancelled my contract over a year ago. I demanded that they fix the account. I did not hear from them again. This morning I received a threatening text message demanding that I pay at least R295 towards “VA account” to avoid legal proceedings. Wonder what will it take for VA to understand that I have cancelled my contract with them.