...she confirmed and said you were good to go and then bailed with that BS excuse, I'd strongly consider calling her out on your local board if you have not done so already (since you can't review her). She had plenty of time to reconsider and cancel if needed.
Providers would black list you in a New York minute for pulling that shit and you'd have no visibility or recourse from them doing it either.
I think a few things can happen here by politely and honestly calling her out, all with appropriate justice to the community.
1) You let other hobbyists know about her recent behavior so they can at least make an informed risk assessment. Also, it really doesn't hurt her review scores since there's no formal review. If it's truly an isolated incident, a single "ding" in a forum won't hurt her much more than it impacted your wallet. Good info for the local guys and a generally equitable outcome.
If she keeps up this practice and guys keep calling her on it, it will quickly have a more profound impact. This would also give other local providers who are good businesswomen an advantage by culling the herd.
2) She uses the forum to provide a response and her side of the story if she so chooses (something we don't get with a blacklist). She can apologize, tell her side of the story, etc., and she may even choose to "publicly" make things right with you.
Either way, I feel this type of situation needs to be brought into the community light