Almost 4 months and no refund.

I've gotten to a point where I'm really frustrated and don't know what else to do. On June 2019 I mistakenly bought R1000 airtime instead of R100. I called telkom and they said they would refund me on condition I don't use the airtime of which I did. They reversed R800 and told me my case was resolved on the 11th of July and funds will be available in my bank account within 5-10 days. On the 31st of July I called to tell them I had not recieved the funds. They asked for my bank statement as proof I didn't receive the funds of which I did. When ever I call for feedback I'm told to re send my bank statement. I called again towards the end of August and it was escalated to a team leader, I waited till September and got nothing. I'm in October now and my money is still not refunded. I'm so disappointed and angry. The service is horrible