kulula date change

My husband and I both accidentally booked duplicate flights on the same date on the same flight. Instead of Kulula's sytem kicking it out, it went though. On discovering this later, I called Kulula who put the one set of tickets on hold and was told that I needed to rebook the flights within the 6 month hold period but that I could still choose flight dates 12 months into the future according to kulula's website availability. Kulula will have this recording. On trying to rebook flights today, i was told that i had to FLY within the next 3 months which is totally unfair and not in line with what was explained upfront. Kulula could neither point me to any documentation on their website that detailed such punitive restrictions. I request that Kulula investigate this and allow me to rebook flights according to availability on their website and in line with what thy originally communicated to me or alternatively refund me. This is totally unacceptable.