Bad service

I bought a ring at sterns mall of the north through laybye, appon buying the ring my wife and I discovered it was too big for her finger one of the sales person told us we can only adjust the size once the price is fully paid, after a month we paid it off. I then asked for the adjustment of the ring but to my surprise Im told I need to pay extra R200 for the service I spoke to the manager and the area manager (annereen Taylor) who wasn't very much helpful. As I told them I wasn't told of the extra cash I need to pay, my options is I either get my ring right or cash back which isn't what I want. But this was the worse service ever. Please on this issue please assign someone else not annereen Taylor as her conduct its bad. I need the ring to be fixed or my money back