Money not refunded, after complaint was lodged

I had recently signed up with Virgin Active Gyms, specifically at the N1 City Branch. I signed up during a period where they had a special running for the month. I was not supposed to be charged any fees for the month I joined. I ended up paying the fees, after realizing this, I went back to the gym and asked that I be refunded as I was not supposed to have paid for the month. It has now been almost 2 weeks since I have lodged the complaint, and my money has yet to be paid into my account. I am really unhappy, as I was promised that I would receive my money within 2-3 working days. I have up to this day received no further feedback, despite additional attempts to get the matter sorted.