Mango Does not want to refund my money.

Mango does not want to give me back my refund... Because their system has a glitch and they messed up my sisters flight they ignore my emails and calls are put on hold for 50min. They owe me R1330 for two separate flights I tried booking. 1st one glitch in system didn't pick up payment then second one I tried to book it in the morning again and they didn't send booking details. When I tried logging on... It kicks me out online.