If you have a good ranking then you should be selling, ranking comes from the sales. Just because you put up a product doesn't mean its going to sell, Amazon is a hard platform to sell on. Keywords help but also external traffic to your listings.
I also notice that the more I would sell of an item the faster it went away from search starting to think someone from the inside is helping outsider buddys for some $$$$ a little just like what is going on in the fba department !
Hey don't feel bad amazon just took my 3 best sellers down yesterday after they was selling really well for months for no reason said all had a bleed problem which I know for 100 % cetainty was not true never had one return or complaint still waiting for a response to why this happened out of the blue yesterday !