curl --request GET \
  --url https://api.returnshelper.com/uat/user/api/Fba/FbaShipmentItem/getFbaShipmentItemList \
  --header 'x-rr-apikey: <api-key>' \
  --header 'x-rr-apitoken: <api-key>'

{
  "data": [
    {
      "fbaShipmentItemId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "fbaShipmentId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "fnsku": "<string>",
      "shipmentItemQuantity": 123,
      "availableQuantity": 123,
      "lastPutawayOn": "2023-11-07T05:31:56Z"
    }
  ]
}