STA Travel refuses to pay holiday refund

A group of us (girlfriends) had booked a 10 day trip to Bali, departing on the 21st of June. Now STA travel are refusing to refund monies paid toward the trip after the agent had assured us we would have a full refund and might only loose the R1000 deposit (numerous emails sent) ; now "a suitable refund" has been given to us ie a credit note to be redeemed in the next 12-24months, and might get refund, maybe in the next 12months.

Again, numerous email correspondence before NEVER, EVER referred to a credit note as a "suitable refund"...for who??? DEFNITELY not suitable to their customer. Now being told about a "Blue ticket holiday"???

Any advice on the next recourse?