Web Africa Double Billing

I've been with WebAfrica for about 8 years. Last year they upgraded my package from ADSL to Fiber. What they failed to do though, is to deactivate the ADSL package and ended up double billing me for a year, I only noticed this a few weeks ago and got in touch immediately. The agent I spoke to admitted that it was a mistake and immediately deactivated the ADSL package. I was told she'll be in touch with regards to my refund. I have been trying to get my refund for about two weeks now. I have to stay on hold for almost 30 mins every time I call and then I get promised that someone will be in touch within 48 hours. I have never received a call back from the WA billing team, I have to keep following up and then I get the run-around. I'm actually on hold while typing this - sitting at 21 mins already. SMH. My decision is pretty easy - If I don't get the full refund I'll just switch suppliers and WA will walk away from a loyal customer of over 7 years. This was not my mistake. I have tried the call center route but I can't see this ever resulting in anything as they simply don't follow up. Do the right thing guys, you *****ed up and it cost me about R5K in the process. #paybackthemoney ;)