Keep calm and let the karma do the work
All the time I spent playing the detective game and getting proofs against ex sellers was worth it.
This is the issue. Our main provider has a second and cheap brand of tools that they sell under another company name. In this way they get customers who are looking for technology (with the main brand), and also customers who are looking for cheap prices (with the second brand). They don't say to customers that the second brand is also from them.
Last months we were talking to our provider to get his permission to sell the second brand with an alt company, but before we do business the manager of the second brand did business with our ex sellers. That pissed us badly, it was not fair that they help those mother fuckers who stole us to compite against us making more damage to our company. This is why I got obssesed to get proofs of everything, because someone had to do justice.
After catching them supplanting the identity of one of our clients (see here), I got an email that they sent by mistake to one of their old email addresses of our company. The mail was for one customer, and the guy wrote something like that the second brand, which is a company from the first brand, give to them the representation to sell tools in our country. And he added the catalogue of the tools where I realized that they offer a modified tool that is not sold by the manufacturer. It's a tool to wich they added an accesory that is a copy of the accesory that our supplier makes and it's patented (that is not legal)... so they are fucking up the company with which they make business.
When I read that email I felt that I won the lottery. I sent it to our sales manager and helped him to write an email to our main provider. It was just one hour after we sent the email reporting the fake website.
This morning before I left home, sales manager messaged me: "they lost the representation, they can't sell anymore those tools". I almost jump of happiness. YES! Kiss my ass fuckers!!!! I ruinned your business!
Finally, karma did the work :)