A promotional allowance is given on certain products for a specified period of time or for all POs written with a supplier. A code 51 occurs when this allowance is listed on the supplier agreement but not included on an invoice.
How to Prevent Valid Code 51s
Code 51s would only be triggered when there is an allowance listed on your PO and it is not listed on the invoice. Because these are only triggered when an allowance is given on your PO, Walmart does not allow disputes through the portal. You should review your allowances before shipping your PO.
Check with your EDI provider to make sure applicable allowances are being included on invoices.
Can it be Disputed?
Only with your buyer. Dispute code Code 51s with your buyer if you can prove that the allowance was actually given on the invoice.
The common scenario for invalid code 51s is that your Supplier Agreement states that an allowance is supposed to be given off-invoice, but your EDI provider is actually giving the allowance off-line-item. In this scenario, the correct dollar amount is being withheld from the invoice, just from the wrong place.
How to Dispute Invalid Code 51s
Send documentation to your buyer.