I have been using a third-party app called "SixBit" to manage my listings, orders and inventory. It's a desktop app that integrates with both eBay and Amazon. I am selling on both eBay and Amazon so this app worked great for me. However, starting this year, Amazon requires all third-party app to migrate to SP-API, and SixBit does not plan to migrate to the new platform. That means I will not be able to use it to manage my Amazon listings and orders. I am looking for another app that can do the job. I receive about 200-300 order a month. Please give me some advise. Thanks