Been waiting 9 months for matter to be resolved

We joined Virgin Active in May 2017 (9 months). We are having issues where the finance department of Virgin Active keeps on phoning us for outstanding moneys, which is not the case. In this 9 months we have made numerous phone calls (25) and sent several emails to Dean Subban @ Pavilion, Durban. He kept on promising that this will be resolved and its now 9 months later. Every time we go to Gym we have to explain the issue to whoever is behind the desk/counter. This is embarrassing for us and we had enough of his empty promises. What to do?