Canceled line at MTN - Still being billed

Cancelled a line in May 2023. I am still being billed for it in February 2024. I have spoken to MTN numerous times, sent mails numerous time, went instore to Northridge Mall Bloemfontein branch, just to get nothing sorted. This is ridiculous. No body is coming back to me. I phoned numerous times. I received a mail in May 2023 saying the line is cancelled, with a reference number. They leave me no choice but to pay the cancelled line, as I have two other lines at MTN as well. And if I dont pay the cancelled line, they will softlock all my other lines as well. R2000 further and still counting! I asked for reimbur*****t, but they are making excuses. They need to listen to calls etc., after I gave them the reference confirming my line was cancelled. Very very bad customer service!!! Still no answer from them. When I phone, I get put through to other departments, but do not speak to anyone that can assist.