Overview

Amazon sellers who submit order‑adjustment feeds sometimes encounter error 18013, which blocks the file because a refund amount is entered as a negative number. The system expects only positive values to represent money returned to the buyer, regardless of whether the feed is XML or tab‑delimited. Fixing the error is essential for keeping bulk refund workflows on schedule and avoiding unnecessary re‑uploads.

Key Points

• Positive numbers required — All fields that convey a refund, such as AdjustmentAmount in XML or item-price-adj in a tab‑delimited file, must contain a positive figure; a value of –12.34 will trigger the error.
• Both feed formats affected — The validation runs on XML adjustment feeds and on plain‑text tab‑delimited feeds, so the same rule applies whether you use Amazon’s API or the manual upload screen.
• No charge‑back via feeds — Amazon’s adjustment engine is built solely for refunds; it will not accept a negative amount as a way to charge the buyer’s credit card.
• Simple correction — Replacing the negative entry with its absolute value and resubmitting the feed resolves the issue in a single step.
• Impact on bulk processing — A single malformed line can cause the entire file to be rejected, delaying refunds for dozens or hundreds of orders.
• Alternative for extra charges — If you need to collect additional money, you must do it outside the adjustment feed, typically through direct buyer communication and Amazon‑approved recharge procedures.

How Error 18013 Is Triggered

1. Feed preparation — The seller compiles a bulk adjustment file, for example a tab‑delimited sheet that lists order-id, item-price-adj, and other columns. In one row the seller mistakenly writes -8.50 for item-price-adj to indicate a $8.50 refund.
2. Upload to Amazon — The file is submitted via the “Upload Feed” interface or through the MWS/SMAPI endpoint. Amazon’s parser reads each line and validates the data types and sign conventions.