MTN Horrible service

I took a contract with MTN in 2016 and my contract with them ended in 2018 and I didn’t do an upgrade when I went this year to closed the contract I was told them my contract will end in 2020 because I didn’t an upgrade in October and I never receive any calls from MTN. I was then told that I need to go to the police station and write an affidavit of which I did and after 2 months of investigation I was told that the same ID number was used for an upgrade. I asked them to search for the cellphone number they used as well as the recording the consultant told me they had a network problem and closed the call. Can you please do more investigation regarding this matter because I’m tired of paying for something that I didn’t receive. My case number is ***