Hi. I was given a skydiving gift voucher for Adrenaline Australia experience which was for $230 at the time and so was my brother in law. The gift voucher states it is valid for 3 years. However, they can change the prices on the gift voucher after 12 months for the skydiving. We now have to pay $60 extra each for the skyding. Is this a valid legal practice? I tried to look through the laws but could see anything on price changing on gift vouchers.