Are you saying she has worked 17 straight days? Or are you saying you had a poor experience and 17 days later she is still on their website working?
This is speculation on my part, however perhaps....
1) I seriously doubt she has worked 17 straight days. Just because a site shows Mary available doesn't mean she has had any requests. It's possible to go a day or two and not be requested. It depends on the Agency business model and screening standards.
2) Just because you have a poor experience doesn't mean 90% of her other encounters had the same issue. Generally speaking or more or less an agency wont get rid of her unless there are a significant number of complaints. If one client complains, it's an incident. If 5 out of 10 clients complain it's a serious trend. This is why I say, give feedback directory to the Agency. The saying "they don't know, what they don't know" applies here.
Lastly, the issue of Agencies banning because of a bad review, I don't support it unless the review is to cover bad behavior in the first place. Sometimes things click, some times they don't. Personally, I'm from the school of move on.
I hope this was helpful, if not my apologies for wasting your time.
Lee Dreams
"Sine amore, nihil est vita