Shark Cage Diving cancelled and NO Refund

We booked for our four sons who were visiting us for a long weekend from Gauteng to go Shark Cage Diving in Gansbaai which is THE place to see Great White Sharks in their natural habitat about three months ago. We paid upfront for the dive/lunchDVD and drive there and back package. The day before the dive (18th July) we get an email cancelling the dive as the weather was bad. I emailed on the Sunday asking for a refund, and then again on the Monday -- NO reply. My husband tried calling several times and spoke to their office lady Pumie, who said that they would do our refund and that she would get Paul to action it straight away -- this was on the 22nd July. Each day we check and no refund. They have now stopped answering the phone as well. and I now have to resort to social media and Hello Peter to get some action out of these guys. We only want our money back, thats all. We couldnt make a new booking as the boys don't live in CT, they are back in Johannesburg.