MTN, Raiders of the Innocent

I have been trying to cancel my contract with MTN since 29th November 2019. I called them 4 times (I have reference numbers to prove it) and have also communicated with them via email. The have billed me for the month of December 2019 and MTN is not prepared to refund me. In my opinion they are a bunch of ******* *****ing good law abiding citizens' money