What do I owe MTN for?

I had a contract with MTn ended last year 2021. I called MTN to cancel my contact on October 10th 2021 and I was advised to call on 10th November 2021 which i did. On March I received an sms that I owe MTN my account is handed to legal. I called the company to get more details what am I owing MTN for and they advise that I call MTN. I've been calling MTN and getting reference numbers and some days their system is offline. Each day I day I get a reference number that query is logged with retention department however i have not been able to get hold of retentions department for my query or get any feedback from them. I am not owing MTN. I called to cancel y contract on the last month of agreement. 11 OCTOBER *** 10 Novemb 14 april *** 19 april *** 26 april *** retention ***