I made a booking on the app for my boys on the 14th of July to fly on the 21st of July

I made a booking on the app for my boys on the 14th of July to fly on the 21st of July. Their app bombed me out on the payment screen, circled forever and didn't go to my banking where you normally accept or decline the payment. We waited a bit and tried again as we assumed the booking wasn't paid for. We also didn't get the confirmation e mail. We tried to make the booking again with a different card...this time using my Nedbank Greenbacks card. The next morning I realized the payment went off twice, once from my cheque account and also my Greenbacks. I have phoned and phoned, they either don't answer and when they do they transfer you to someone else and then drop the call. When I eventually got to speak to someone they said I should e mail which I have many times. I have followed up on numerous occasions to no avail. Only when I threatened to email Hello Peter did they answer my e mail. They now tell me they only pick up one payment even after sending them proof of payment. Now silence again.