Amazon assigns an ASIN to a product, not to any individual seller. E.G. a standard 40 pack of PG Tips tea bags would (or rather should!) have the same ASIN no matter who the seller is.

If you've been making and/or selling a product without holding design rights or any protection you have little argument as only the rights holder can challenge.

If however you also hold design rights then you can challenge, within Amazon brand registry should help you if you've registered it, otherwise you may face a court struggle against both Amazon and $WeaShaemgLi if they can be traced.