REFUSING TO CLEAR MY NAME

My account was handed over and last year to mbd inc and I have paid off the account last month. I send over a letter to mtn to confirm that my account has been paid in full therefore requesting them to clear my account. I receive an email from the legal department informing me that I have missing invoices from *** to an amount of R2359.00. I paid over R5000 since last year so where are these missing invoices coming from? First they list me twice for one account now there are missing invoices. Please can MTN rectify this or this matter will be taken further. I want my name cleared and my account closed at MTN. I will not pay for that R 2359.00 that I have no knowledge of. This is ridiculous and I will not be ****** by MTN.