Terrible service

Good day I thought I was getting the best service possible. Unfortunately I was wrong.. Network is terrible. Cannot use more than one device at a time. Even with one device... It buffers. Numerous complaints about their network.. To no avail. I canceled in the 3rd week of January. Received a confirmation that my Sim will be canceled by the end of the month but my last billing will be on the 1st of Feb 2021. Why should I be billed if I canceled the service.i called in numerous times but is always told the same thing. They are offline and can't give me an answer.