Amazon wants to control third-party sellers’ product pricing
Stop selling your stuff on Amazon. eBay is better. If you're too large to sell on eBay, then get out of retail right now, are you crazy? Selling products other people make used to have bigger margins because it was a lot of work (opening and running a store). If your only work is buying stuff wholesale and boxing it up and sending it to Amazon then you, frankly, don't deserve much profit for a few hours of monkey level work.