Account paid up but still listed on credit beruea

I had an account with MTN, I owed money on that account, I settled the account as per VVM request, I've emailed proof of payment, this was in mid October 2015. I emailed MTN-vvm to request a letter to advice that the account is paid up and to close the account so it can be cleared at trans Union, nothing has been done. We are harassed day after to pay off outstanding accounts, we do that and when it's for us the client/customer to get feedback and get our names cleared we have to call daily. I called vvm this morning, the consultant put me on hold for 15 minutes saying she's going to speak to her supervisor. I had to hang up as I'm using my cell phone to call. Can this matter get sorted out ASAP. I want nothing to do with vvm and MTN.