If account is activated (settings enabled, custom column is showing), check this link to see if Facebook is receiving data from Amazon without errors.
Login to your FB Business Manager.
You may see default assets such as your website FB Pixel.
Scroll down and find assets that have Zontracker in the name ("Amazon purchase zontracker" is common).
You will see activity in the form of numbers other than zero, "currently processing", a green colored activity signal (it may be orange, suggesting it was active but then went inactive), "last received x minutes/days ago".
If you don't see any of the above, it may say "No events received" and be gray-colored instead of green. This means data is not being received.
IMPORTANT: You need to upload your data regularly to Zontracker to see updated data in FB ads Manager (Learn how to upload your data here). Regardless if it was from FB ads or any organic/paid Amazon order, the activity for Zontracker will only show after Zontracker is activated and data is uploaded to Zontracker (previous orders/data may also be uploaded). However, please note that even if you upload their CSV reports daily or have a SellerTools integration, the sales will show up in their Ads Manager only after Amazon ships the order. If you don't see activity instantly and you know the order's been shipped, please create a support ticket with Zontracker.