NO COMMUNICATION NO RESPONSE

I ran into financial difficulty and missed some payments on my MTN account. they handed me over to some debt collectors without informing me, when I was up again financially I paid my instalment to the MTN account only to find that I wasn't supposed to, the debt collectors informed me that I had to pay them and I did until my account was settled. now I am trying to get hold of mtn to inform them that I have settled the account with the letter and also for them to refund the money I paid them instead of Norman Bisset. I am very disappointed with the service because my name has been listed and I cannot get them to clear my name.