CS Amazon Integration & Sync

We installed this app 3 days ago since Shopify's Amazon channel is being deprecated. About 25% of the Amazon orders that this app has imported into Shopfiy have been duplicated, some orders that it imported it went ahead and marked as fulfilled even though we haven't fulfilled them, SKUs aren't syncing or aren't showing up in the app even though they exist in our Amazon store. We've reached out to their support email and they initially responded after several hours but it's been more than a day now since we've gotten a follow up and we've sent multiple tickets (one for each issue we see). They haven't been able to resolve a single issue so far. It's a mess!