Trying to close a MTN cell phone contract.

If I could give a minus start I would. I immigrated from South Africa in June. I closed my cell phone account in the last week of may 2023. I am getting billed every month. I do not have any bank accounts or anything left in SA and I am mailing MTN every month but no action is being taken, my bill is now over R2000 and I am not going to pay it as I closed two accounts but one is still active. I am sending mails every month but it seems like they not interested. I am asking if there are any competent people in MTN to assist with the closure of this account.