Unable to cancel prepaid account MULTIPLE TIMES!

I have been trying to help a friend who moved overseas to cancel their MTN prepaid account MULTIPLE times now, for more than a year. We have tried multiple channels after being assured in 2022 that the account was indeed cancelled. We have all the email correspondence and still the account hasn't been cancelled. This whole process has been utterly ridiculous and frustrating. Now MTN are sending threats of legal action and our attempts to contact MTN have gone absolutely nowhere. Our next option is taking the complaint to ICASA. Hopefully, someone from MTN will contact us and actually resolve the issue instead of us having to escalate it to ICASA.