Payment Debited from my account and booking cancel

On the 31/03/2015 i booked a flight to Cape Town via the Mango Airlines website using the SID payment option. An amount of R1877.00 was debited off my account and when I logged on to the website for confirmation the ticket was cancelled. I subsequently called Mango to enquire about the ticket and they said I need to send proof of payment which I dont have as I used the SID option. Why offer this payment option when it clearly does not work.<br>