MTN is failing me.

I have a cellphone contract with MTN, on the 17th April 2020 they disconnected my line and when I called them to enquire they gave reasons that I haven’t been paying my account from December 2019 till April 2020 which is not true. Then I went to one of their stores to present my proof of payments were they told me that there’s nothing they can assist me with as my account has being handed over to MBD legal .I contacted MBD , emailed them my proof of payments till to date( because I continued to pay my account even when my line is off)but still they insist that I pay the money overdue . I have used the EFT payment method and the “MyMTN “ app with my cellphone no and account no as reference. What more should I do. Now is like I’m taking a fall that MTN fail to trace my payments in their account. I believe that MTN should be the ones to resolve this problem as MBD doesn’t have access to their accounts , they have to track my payments and reconnect my network.

It’s six weeks now stuck with this unresolved issue, they even went to an extend of disabling my phone .