Airlink bad experience

Worst service ever, we booked a return ticket from Richards Bay to OR Thambo, on the day of the flight we were advised that the flights from Richards Bay had all been cancelled. We had to make a new booking on another airline from Durban to OR Thambo and had the additional expence of having to travel to Durban from Richards Bay. Tried to get a refund for the ticket and was advised that we could not get a credit but would be able to reuse the ticket at another date. Now trying to book this ticket is impossible. Why not just credit me for the ticket if you can not supply me with the service???