Long refund time after many empty promises

After booking a flight through the website, and then changing the booking through the call center, due to the fact that it was a BA flight, the agent on the phone provided me with the incorrect booking fee change. Upon getting the invoice, I immediately contacted the contact center regarding the error, I spoke to Candice and gave her all the information required. She carried on to then tell me that she would listen to the call to check whether the error was made on their side. She contacted me that same day and informed me that the agent on their side did give me the incorrect amount and that a refund would be processed, which would take between 4 - 6 weeks. She was very helpful and quick to respond, however this was nine weeks ago and the refund is yet to be made. <br> <br> I have contacted the call center several times and have been told each time that a supervisor will contact me. I am still waiting. I have also requested an email indicating that the refund is being processed, which obviously has not been sent. <br> <br> This is very frustrating to have to deal with this incompetence especially when the mistake was made on their side.