Sometimes things change and you want to depart your Stay earlier than expected.
Of course, you are not bound to remain in a Stay for the entire time you've booked and can leave early if you wish.
If you would like to seek a refund from the Stay you should start by discussing this with your Stay Host and seeing if you can reach an agreement for a possible refund. As the Stay may not have any opportunity to replace your lost booking easily, or at the last minute, they may not be open to accommodate a refund easily.
It's also worthwhile reviewing any Travel Insurance policy you have in order to see if the cost of early departure or alternative accommodation is covered under your insurance policy.