Account handed over to legal

Good day

I took out an insurance contract with mtn in 2020 with reference A*** and due to the unforseen circumstances it was handed over SSDA and l paid off the account in August 2021 and when l requested for the paid up letter and only be told that there is a balance and no update was done on transunion. My contract line was disconnected from mtn however they continue to bill me and every time you call you are told the account is with legal and promise to send the balance and to date have not received anything.l just want to settle my account and be removed from transunion