If you need Amazon Seller Central statements containing transactions older than 90 days, you need to request them from Amazon. By default, Amazon archives statements after 90 days.

Follow these steps to unarchive your Amazon Seller Central statements:

1. Login to your Amazon Seller account
2. Click Reports > Payments
3. Click All Statements
4. Locate the desired time frame(s) then click Request Report

Important Note: Make sure you find ALL the reports for your requested time range, or our system will not be able to pull your requested data.
Keep in mind that settlement reports may have beginning dates before the dates you request, those reports will need to be unarchived as well. Additionally, keep in mind that all reports for your requested time frame will need to be unarchived. For instance, if you use Amazon Seller Europe, and request historical data for your UK Amazon store, you will still need to check Amazon FR and Amazon DE etc. to see if any Amazon reports need to be unarchived for the requested time period, even if you don't typically sell in those regions. Another place that reports may be hiding is in the dropdown for "Account type", there may be a report for a single invoice based sale, even if you don't typically do business in that way

Once unarchived, Greenback is able to access the transactional data. Amazon will archive them again in 90 days, but the data will now remain in Greenback.

While they are accessible, you are essentially sharing them with Greenback just like they were new transactions being auto-fetched for you. There's no need to worry about duplicates; Greenback always searches for matching transactions and prevents them.