for a provider you actually didn't meet in person, so that option is out.  You can post or link her info on this board to get the word out that she is a scammer, but not sure what other options would be effective.  Murder is still against the law.  

write on the blackboard 1,000 times:

I Will Not Pay A Deposit

 
There is a category of Rip-Off reports, but as CDL suggested, hard to create a report without an actual meeting. Even if you could, guys tend to search reviews by city so like your post here, it will get lost quickly. Also, her booker will already have an alternate version of events to dispute your "review."

On the bright side, what goes around comes around and someday they'll ripoff the wrong dude.

I was checking the Profile of a popular touring Provider. She also travels to Europe and advertises on  
a eurogirls escort website. That website actually provides a warning:  

"WARNING FOR VISITORS TO [geographic area of the person I searched]:
ATTENTION - NEVER SEND MONEY IN ADVANCE if you book an escort service! These Ads are most probably SCAM! They usually require your verification as a new client by sending a certain amount of money by PCS coupons, Google play card, PayPal etc. It is very difficult for us to reveal these fake Ads as they look like any other regular Ad. Please, send us a link (URL address) to [email protected] in case you find such Ad on our website.

Si vous souhaitez réserver une escorte, NE JAMAIS ENVOYER D'ARGENT À L'AVANCE! De telles annonces sont probablement des arnaques. Habituellement, ces filles exigent votre vérification en envoyant une certaine somme d’argent par des coupons PCS. Il est très difficile pour nous de révéler de telles annonces factices, car celles-ci ressemblent à des annonces classiques. Si vous trouvez une telle annonce, veuillez nous envoyer un lien (adresse URL) à [email protected]."
.
Please pardon my French, errrr, their French.

TER makes exceptions for ripoff reviews. Where money was given but no meeting took place, reviews are allowed. At least sometimes. It may be on a case by case basis but there are many reviews in the database where no meeting took place.  
Here’s a recent example from a few weeks ago

https://www.theeroticreview.com/reviews/detail/marianna-maison-review-by-ems71-2204266

Here’s a profile from 2015. All 3 of her reviews no meeting took place.  

https://www.theeroticreview.com/reviews/emily-6575494118-279162

Another profile below from 2017. Four out of 5 of her reviews are ripoffs where no meeting took place.

And don’t ever send a deposit again. (But I assume you figured that one out😊)