Why Can a Duplicate Sale Happen?
Cross-listing allows the same inventory to be offered on Amazon and eBay.
When an item sells on one marketplace, the inventory change must be received and processed before the corresponding quantity can be updated on the other marketplace.
If another customer purchases the item on the second marketplace before that inventory update completes, a duplicate sale may occur.
Other Possible Causes
A duplicate sale may also require investigation if:
The eBay account was disconnected.
An inventory update failed.
The Amazon quantity was incorrect.
The eBay listing had a higher quantity than expected.
The cross-list association wasn't functioning correctly.
A marketplace API request was delayed or unsuccessful.
eBay notes that keeping listing quantities current is important specifically to avoid overselling. eBay
What Should I Check?
Check the order history on both Amazon and eBay and note the exact date and time each sale occurred.
Also verify the quantity that was available before the sales.
What Information Does Support Need?
If the same unit sold on both marketplaces, contact AccelerList Support and provide:
ASIN
Amazon SKU
eBay Item ID
Amazon sale date and time
eBay sale date and time
Quantity that should have been available
These details allow us to review the timing of the inventory updates and determine what happened.