Retailer Guides9 min readFebruary 20, 2026

Why Your Supplier Is Getting Chargebacks from Costco (And How to Stop It)

Costco chargebacks can devastate supplier margins. Discover the most common causes — late ASNs, incorrect PO acknowledgments, label errors — and how to eliminate them permanently.

Costco sends chargebacks to suppliers for a variety of EDI-related issues. The most common causes are: late or missing ASNs (856), incorrect carton counts, GS1-128 label errors, and PO acknowledgment failures. Every chargeback reduces your payment and can damage your supplier relationship. In severe cases, Costco may review your supplier status. With EDIPlug's automated ASN generation and real-time document validation, most chargeback causes are eliminated at the source before documents are ever transmitted.

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New to EDI? Learn exactly what Electronic Data Interchange is, why major retailers require it, and how growing businesses can get compliant fast — without the technical headaches.

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How to Start Selling to Walmart: EDI Requirements Explained

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EDI 850, 856, 810 — What These Document Numbers Actually Mean

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