I had a month to month contract

I had a month to month contract. I tried to cancel it because the data goes very faster then any other network. I returned it to the local mtn shop in Riversdale on December 2⁹th . As on today 16 feb 2026 im still getting billed even more than i was charged initially. I called the call centre more than 20 times ro cancel. They're unable to resolve this matter.