Can anyone recommend a third party that deals with hijackers?

Long story short we developed a product under our name and it’s doing well until hijackers selling a different brand started using our listing to sell under.

Out trademark is still pending after 11 months so we can’t report them through brand registry until it’s registered.

I’ve done test buys for both of the current hijackers, one came in yesterday of course it’s a different brand from ours still waiting on the second, we don’t distribute our product for resale we only retail it ourselves and there is a cheap generic brand which we know that everyone else sells. I well documented the first one with pictures and a video of me opening it and reported it as seller abuse, selling a different product. You can’t send pictures so I sent a link to the video, not sure if that even matters or if anything will be done at all I’ve read it’s hit or miss. I’ve contacted both sellers explaining what they are doing is against policy to no response.

Obviously this is doing a lot of damage, not only to our sales but to the reputation of the product we worked our tails off to produce and fight Amazon to allow us to sell.

Assuming the test buys and reporting of sellers do nothing I know there are services that deal with sort of thing although I’m not exactly sure what they would be doing differently that we can’t do or have done. Hopefully they just know what they are doing better than we do and can help. Regardless I would sincerely appreciate if anyone has any recommendations…

Thank you very much for any help