Telkom never ending contract payments

In 2016 I finished paying off a contract that I had taken with Telkom mobile. The contract was for 2 Samsung tablets. I had been paying manually at ABSA bank until I made my last payment. Now, over the weekend I went to Telkom mobile at Newcastle mall to takeout a cell phone contract & was informed that R399 was still outstanding on an old contract.

I want to query this because I had made payment arrangements with Telkom after I reported them on Hello Peter due to them saying there were outstanding fees after the conclusion of the duration of my contract. I cannot remember the name of the consultant but he had told me how much I would have to pay to finish off the outstanding amount & the banking details. I oaid everything down to the very last instalment. Why didn't they write off my contract after I made the arranged last payment?

I feel like i'm being ******.