curl --request POST \
  --url https://api.returnshelper.com/uat/user/api/Fba/FbaWarehouseInventory/assignReferenceNumber \
  --header 'Content-Type: application/json' \
  --header 'x-rr-apikey: <api-key>' \
  --header 'x-rr-apitoken: <api-key>' \
  --data '
{
  "fnsku": "<string>",
  "referenceNumber": "<string>",
  "warehouseId": 123
}
'

{
  "data": {
    "fbaWarehouseInventoryId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "warehouseId": 123,
    "warehouseDescription": "<string>",
    "fnsku": "<string>",
    "referenceNumber": "<string>",
    "remark": "<string>",
    "quantity": 123,
    "availableQuantity": 123,
    "modifyBy": "<string>",
    "modifyOn": "2023-11-07T05:31:56Z"
  }
}