Billing after cancelation of services

I had two accounts with Supersonic, one was used at home and the other for my new place. I wrote an email requesting that my accounts be canceled on 28 June 2023. Both services stopped working as of 1 July. I got a confirmation of confirmation and was asked to return the router I was supp**** with. Five months later, I am still being billed by them. What's more confusing is the billed amount ranges from R50 to R864. My monthly fee was R399. So I don't know where these amounts are coming from and why I am being billed still. I emailed them asking this question on 16 November and to date, I have not received a reply. The support center is so frustrating as you never get the same answer and have to reach out multiple times to get help. Bank charges are accumulating because of them. This is awful and costly lack of service.