refuses now to host my event

What a nice stunning venue but a problem we booked for my dad's sixty-th in 2020 just before covid. spoke to the owner to get deposit back refused but told us we can use it for a next event. Yes its 2 years but how many people have big events every month. most people don't I asked now to book for my 40th knowing we have this pre paid now tells me it's only valid for 18 months. no where even on her quote does this state 18 months. I do understand every one suffered with covid and we are not asking our deposit back but want to use this stunning venue for 40th now she refuses.