Hello @James Carlo Languban
You should use RestLet for retrieving data from Amazon FBA. Because Amazon charge two types fee on FBA orders
Order level fee
1. FBA commission
2. FBA Perunitfulfillmentfee
3. Fbashippingchargeback
Etc.
Other fee
Service fee
Adjustment fee
Etc.
For other fba fee you need to create Journal entry for these and map NetSuite account accordingly