MTN fails to cancel my contract even though i paid the full early termintation

I called on the 22 April 2021 to cancel my contract early as i was leaving the country. The agent on the phone said she would email me indicating the early cancellation fee amount and procedure. I still have the email. I received the email after the call and then proceeded to pay the early termination fee. Since then i have been continuously been receiving statements for payment and have made numerous phone call and empty promises. I have send various emails to various agents and also no response or help. My contract is still active and I am in another country and I simply do not know what to do next. I am absolutely disgraced and frustrated that my contract was not cancelled. I followed the instructions and did my part and now my excellent credit record is rapidly being affected. Can anyone advise or help? I cannot get through to the call centre and my emails are ignored