Amazon launch

Hi, This post is just for an experienced Marketer. I launched an Amazon Product a few months ago. Product was doing well but due to new sellers coming in niche and competition is rising. Now I want to hire an Amazon PPC expert because I hired two so-called experts from Facebook groups But they have done nothing. Please share your previous work of listing and PPC. Also, share the stats of achievements. I will evaluate and interview you before hiring.