A lot of providers don't actually know each other in person, and the rivalry and jealousy is all in people's heads.
This rivalry and jealousy yes does exist and can turn very ugly. Booking false calls by jealous providers leading to a no-show is far from being isolated incidents.
Since screening tends to somewhat hinder that venue the next line of attack is spreading bullshit. This is very effective and will spread. You indicated having tried this, not against others but concerning intel about yourself, and saw how effective this was.
But I wouldn't worry too much about this since most of us don't really care about the negative noise. Honestly, it plays a lot more against the instigator than for.
In any case if I were you I'd tell the provider that someone is bad mouthing them, might save them a lot of trouble.
If it were life threatening or really personal stuff, yes of course. But in the day to day of this domain I don't see any advantage for the lady. Really, I see the complete opposite.
Why go and stress her out with such news that in reality she has no power over? Imagine a moment a sucessful woman getting news that someone is bitching about her. Where do you think her thoughts will go? On her good clients that she met that day? On the pride she has for having built a good image of herself etc?
No her thoughts will go to the one and only incident of someone talking shit about her, will eat away at her down to the pit of her stomach and will negate all that was positive for the day. Sadly, this hurt may last hours and maybe even days.
Is it really worth it?
This is an extremely cold and hard domain. Thank G that the positives overweigh the negatives. Like
@Cap'tain Fantastic said bullshit is spread in all lines of work and life in general. This domain is no different and is to be expected tenfold.