Pathetic. Still getting billed months after cancelation

Please tell me why 8 months after I canceled my contract with MTN, I'm still getting billed.

I took out a home wifi contract with MTN in August of 2021. The application process was pretty quick and smooth and I received my sim card. But then soon I realized that the network was absolutely useless in my location. Called them a couple of times to resolve the issue, to no avail. So I decided to cancel the contract.

On the 22nd of December 2021 I called to cancel and was told I'm gonna have to pay an early cancelation fee of R917.06, which I gladly did. I even received a confirmation email that my contract would be canceled. 3 months down the line my account gets debited and I receive the bill from MTN. When I try to call them, they give me the run around and keep transferring me between departments until I tire or the line cuts.

What really ****es me off is that they admit that on their system they can see I tried to cancel my contract, but no one can tell me why I'm still getting billed. And everyone knows MTN/Mondo has trained their staff to act rude/stupid whenever they here a client mention "cancelation".

I'm so sick and tired of these two companies. Please do the right thing. I've emailed you the proof even though you already have it on your system. And this is really affecting my credit score.