Waiting for Refund to be paid

In November I had made an EFT payment to Telkom for the Cellphone and Data packages I have with them. I was also debited for an additional amount as according to Telkom's records there was an outstanding amount. I calculated the EFT amount and the amount Telkom debited from my account and there was a difference which needed to be refunded to me. I contacted the call centre and was told that I needed to wait 48 hours as they cannot see the EFT amount reflecting on their side. I did this and called back 3 days later and was told yes they can see theres an amount that needs to be refunded to me. I was given a case number and told that it would take 7 to 10 working days for the amount to be refunded to me. This was on the 1st of December 2017. I calculated the days and on the 15th December 2017 I checked my account but still no refund. I called into the call centre and explained my case and was told the case has been resolved on their side. I explained that I still have not received my refund. I was advised to send through my bank statements to prove that the refund was not paid, which I did. I waited till after the new year and on the 4th of January I call the call centre again explaining my case. Informed the agent that I had sent through my bank statements ect and still i have not received my refund. This back and forth has been going on almost on a weekly basis and it is now the 12th of February 2018 and still I have not received my refund. I keep getting told that it will be escalated and someone from their accounts department will contact me and provide feedback. That has never happened. I would like this to be resolved ASAP as I cannot continue to be contacting Telkom's call centre and hearing it will be escalated. It would be nice for someone in the accounts department to contact me and hopefully we can resolve this issue.