Wicked karting refund

My and my family drove from Durban north to the galleria location and were not able to race. We arrived at lunchtime and paid for 4 people for 20 minutes (R200 each for a total of R800). We waited 40 minutes for our turn which was understandable. What is not understandable is that when it was finally our turn we were told that only 3 karts were working. We could have been told this when we arrived. We waited another 40 minutes while they tried to fix a kart. 2 other people went ahead of us as there 3 working karts. These people did 2 laps before their karts broke down and they couldn't race either. We asked for a refund and were told this is not possible but were given a voucher. The voucher is only valid for 1 week. I do not live in Durban and will not be able to use this voucher so I would like my money back but was told a refund is not possible. We should have been told when we arrived there that only 3 karts were working, and even then that the karts are not reliable as they broke down after 2 laps when the people went ahead of us.