If what you’re saying is true, it is absolutely despicable what this other seller is doing.
If you have reported this numerous times and nothing has been done… I would stop reporting, take a step back and try to come up with a game plan.
I went through some of the feedback’s… If they are somehow setting this up, they are doing a great job because I cannot tell which are fake and which ones are real. I’m thinking if I cant tell, no way Amazon will go through IP addresses, transaction records and feedback history of the reviewers unless its blatantly obvious.
That being said… you will need to gather enough proof so Amazon will at least look into it (they probably receive hundreds or thousands of reports a day.)
I would go through every single feedback not just theirs and yours but other competitors, If they are doing this to you they must be doing it to others as well.
I noticed one buyer left you a 1 star and also left another competitor a 1 star on a similar product, I would look into these and try to link them even to go as far as contacting other sellers (maybe they are trying to collect evidence as well)
I also noticed the feedback’s they receive often times mention how great and easy it is to set up but then refers to great customer service like (Barbara from CS was great for example) Why do you need CS if it was so easy to set up?
Either the feedback’s are real or they offer their buyers an incentive to leave very detailed
5 star reviews, I do not think they are stupid enough to do this through amazon messaging (maybe through the mail… 5 star review for an extra camera to follow or something like that)
Have someone do a couple of test buys and see if they are contacted (worth a shot,
I’m sure you know not to leave feedback or reviews on your purchase or collude with other sellers to shut them down.)
You will need to prove these discrepancies to Amazon so they will at least look into it. imho you should not bombard them with please investigate reports, they will ignore your complaints after awhile.
Sorry this is all I can come up with at the moment.
Good Luck