Shopify Marketplace Connect

Okay this app literally does not do the single thing it is supposed to do, which is syncing your pricing and inventory counts to 3rd party marketplaces. I have spent hours on chats and videocalls with support and they have absolutely nothing for me. It's with the developer team which is laughable because I am asking for the most basic functionality of the app to work the way that all of their reps expect it to work. Just an utterly unusable product.

Update: they finally got it working. All was well for a few weeks until I realized all prices were marked up by 5% on Amazon. All settings correct and unchanged. Support is trying but super unsure what is happening. Unusable app I don't know how Shopify endorses this