MTN is ****

I am having problems with MTN and their Attorneys VVM Attorneys. I had a contract with MTN in 2017 March, during the year I was retrenched and could not pay the monthly installments, MTN handed over my Account to MBD Inc, i told MBD that i will pay as soon as I get a job, January 2019 i got a Job and started paying MBD end of Feb. OKAY, End of May i receive a call from VVM Attorneys claiming that my MTN account was not paid for over a year and my amount owing was not updated with the payments I made to MBD, I explained the above story to them and they did not understand, I called MTN about this VVM issue and told me that my account was moved from MBD Inc to VVM. I did not mind paying VVM, my problem is why do i need to pay from the beginning like i never made payments to MBD. Now VVM is threatening to take my name to ITC which is gonna make my name even more DIRTY. can someone please assist.