@Melissa1730 No, you lost your money because you cancelled a reservation and were subject to the terms of the cancellation policy you agreed to when you booked, not because the host is a scammer. Had she not said she would refund you, you still would have lost the money. When you book a place, you are entering into a contract and are subject to the terms of the cancellation policy.
I am by no means condoning the host telling you she would refund you if she got the dates rebooked and then reneging on that. There's no excuse for lying like that, promising something and then not honoring it.
But guests are bound by the cancellation policies when they cancel. The host is under no obligation to refund, regardless of what they may say they will do.
Had the host never made that promise in the first place, how would that have changed you losing the money? You apparently couldn't keep the booking due to your medical issue. So how would her not offering to refund have changed that situation? Would you have kept the booking and stayed there?
Another thing to understand, although it may not apply in this case, is that just because you see dates you cancelled subsequently blocked on a host's calendar, that doesn't necessarily mean they got rebooked. Hosts can block dates themselves for all sorts of reasons. They may decide that since the dates got cancelled, they will use that time to do some renos, or to take a holiday themselves, they may have friends or family coming to stay.
So the host may have lied to you, which is certainly unethical, but she didn't scam you out of your money- that happened because of the cancellation policy.
This is what travel insurance is for- to cover yourself if you have a travel issue. Had you spent an extra $60 on travel insurance, you would not have lost all that money.