22 days way passed they still investigating

It makes no difference that you respond here on hello peter and don't investigate or get back to the complainant, you might as well not respond at all because its no use am still not assisted. Good day I had contract with mtn however things went bad was out of job ,I couldn't pay anymore, it was handed over to MBD I tried to pay and i didn't manage to pay at some point. I got a job and called MBD to inquire about my outstanding balance, i was told the debt is closed on their side therefore it was taken back to MTN i contacted MTN and was told its purged internally , I asked them for a letter that says the account is closed on the 5th of January till this date i haven't received any correspondence , i don't know what to do anymore.