*********** company credit company harassing me for payment that has already been made in full

I had an outstanding Nsfas student loan which I needed to pay. I was told to make a portion of the payment by 31 December 2018 from Nsfas.I paid R2000 on 15 December 2018 And then 25 January 2018 I paid the balance R13 564. Then i had credit intel sending me messages to make payment I contacted them to say payment was already made in full and I emailed both payments to a Toni M he did not reply back to me I then tried contacting him a few times when I got hold of him he advised he was to busy I said I just want an email confirming receipt which to date I got nothing. I phoned and spoke to a lady who said that she can see payment is made but she needs to check with management to take my name of the list. she hasn't got back to me. I emailed Tony again, he then emails after a week or two to now say he needs a statement. I emailed him a statement from nsfas and copied in their email below ********** I still got an email today 4th April 2018 stating that I have outstanding monies due and I will be handed over. I sent my email with the statement again to show that all payments are made and I have a zero balance .

This is rediculous, is this a company or a circus as no one is clearly doing their jobs. People who are not paying should be harassed. I don't know what else to do to get through to these people or how to get them to read their emails. I refuse to go on to credit bureau for something that has been paid in full due to lazy *********** people. Thus is happening from January to date?