Amazon sellers say they've been hit with multiple policy changes all at once. Bloomberg/Getty Images Amazon sellers say they've been frustrated with recent policy changes on the e-commerce site. A change announced in April regarding ad payments sparked a sellers' boycott. As a result, sellers are diversifying their sales channels, using platforms like Shopify and TikTok. On April 2, some Amazon sellers got an email that many saw as a breaking point. Starting April 15, Amazon said, their advertising costs would be deducted from their retail proceeds first, with a credit or debit card used only as a backup if those proceeds fell short. For sellers already contending with delayed payouts and new fees, the change felt like the last straw. Under the old setup, sellers could pay for advertising on a credit card, collect points, and benefit from the extra time before the bill came due. Under the new approach, ad costs would come out of proceeds first, reducing float and tightening cash flow.…