Disappointed Customer

I cancelled one of my contracts last year (January 2019) and one was due to end March 2020. It turns out, MTN has still been billing me for the contract I cancelled in January 2019. I never noticed because the two contracts were billed as one account. I only realised after I cancelled the second contract in March 2020. The worst part is that I have received no data, call minutes or sms bundles for this contract since February 2019. I have tried without success to get assistance from them. MTN come on, I am due for upgrade soon, and I don't want to change service providers due to poor service. I need my money back and this contract cancelled. Thank you.