Not from Amazon but this happened to me when I had an app in the top 10 of the AppStore. This a-hole from Silicon Valley flew over to London, asked me loads of stuff, saying he wanted to buy it, offering large amounts of cash and then just launched his own version and some copies of other things I’d made. I’m still not sure if it was his plan all along or not - He did try and recruit me to his company at one point but when I refused, his parting words were “if someone offers you a seat on a spaceship, don’t ask which seat”. Really glad I didn’t take that seat.
If that is the case I don’t think it’s policed at all. You can’t copyright or patent an idea so people just do what they want - at least when you’re an indie developer.
