@Brianna143 Personal circumstances are not grounds for cancellation refunds. Hosts aren't responsible for whatever life circumstances might befall a guest- it's a business deal, not a friendship.
The host has no obligation to waive their cancellation policy- they aren't doing anything wrong, they aren't being rude by not refunding you more. You agreed to the cancellation policy when you booked. That you didn't understand it is unfortunate, but doesn't mean you are being cheated or have a leg to stand on to take them to court- it's you who is being unreasonable, not the host.
Cancellation policies are based on the full price of a booking, not on what you paid upfront. This is clearly stated in the cancellation policy information if you bother to read it.
If Susie books Happy Home on the Hill for 3 nights for $150 and pays in full at the time of booking, and then has to cancel, Susie gets $75 back.
If you book the same listing for the same price, but only pay half up front, why should you get half of the $75 you paid back?
In both cases, you and Susie are both out of pocket $75 of the total booking cost, which is as it should be. Why should Susie be penalized more for cancelling than you are?
The option to pay half up-front is simply a payment convenience offered to guests- it is completely unrelated to the cancellation policy and the % of refund owed.
Sometimes hosts will offer to refund more if they are able to rebook the dates you cancelled, and you could ask the host if they would be willing to do this, but honestly, as you have incorrectly faulted the host for your own misunderstanding of how refunds for cancellations work, I doubt they would be willing to work with you any further.