A shortage occurs when you send an invoice to Amazon for a number of items that are higher than the quantity received. The discrepancy between the quantity invoiced and the quantity received results in what Amazon calls a Purchase Quantity Variance (PQV), which results in a shortage claim.
A shortage occurs when you send an invoice to Amazon for a number of items that are higher than the quantity received. The discrepancy between the quantity invoiced and the quantity received results in what Amazon calls a Purchase Quantity Variance (PQV), which results in a shortage claim.
Shortages are due to the following causes:
- Catalog setup
- Advanced Shipment Notification
- Invoicing
- Labeling
- Vendor Lead Time
- Delivery Compliance
- Inbound Receive
- Loss Prevention
To dispute a shortage claim, you’ll need to provide the quantities, barcodes as well as shipment date of each item. To start the process:
1. Select Payments → Invoices
2. Click the Review/dispute shortages button
3. When you access this tool, a list of invoices affected by a shortage claim is displayed. To start the dispute, click on the Action button, and in the pop-up window, click Dispute shortage by ASIN.
4. The shortage claim dispute process requires that you provide additional information for each item/ASIN which was deducted from the payment of your invoice. Select the individual lines you want to dispute or click Select All.
5. Fill in the data in the Dispute Quantity, Shipped Product, and Shipped Date columns.
6. Add Comments and enter any additional information to help Amazon in its research and click Save. (We suggest that you provide as much information as possible to confirm your claims. Information such as the ASINs for the shipment and images of the carton level label can expedite the process.)
7. Click Continue.
8. Provide the Dispute title, Dispute summary, Optional items, and Supporting documents. 
9. When done, click Continue. Review your dispute and click the Submit button to complete the process. Amazon will initiate an investigation based on the data submitted.
Training reference here
