It is ridiculous that you can order a supplement where it says "sold by Proctor and Gamble, fulfilled by Amazon" on the product listing, and then receive a counterfeit product that was sent in by a different company. If they received it from a different company, then it wasn't "sold by Proctor and Gamble."
At the very least they need to give brand owners the tools to protect their brands- an option to put non-authorized resellers' shipments into a separate comingled bin, and have all the authorized resellers in another.
Right now the only option for a brand with a popular product to protect from counterfeiting is to not sell anything through Amazon and sue everyone that tries to list your products on Amazon- which might not even work and really hurts your market reach.