rex airline

hey Ray can some one explain to me how Rex Airline can take over $1000.00 for 4 people traveling to sydney return back on January10 and now we cant travel - covin19 and we want to travel next May hopefully when all over and they tell me fare is only good for use 12 month from first purchase. we dont want our money back and they have our money for 17months we just want to travel on changed dates - is that so hard !!!!! we are happy if there is a small charge - no problem BUT to lose over $1000.00 and they are screaming for money off the goverment. unfortunately REX is the only airlines in regional australia so have us by the short and curls ( pardon the pun).
Prefer if name not used as have family member working for them - but cant help me