How long does it take to restock eBay Quantity after a sale?
Normally, it will only take a few seconds to one minute to restock your eBay Quantity from the Warehouse Inventory.
Why eBay Quantity is not updating:
Restocking quantity may fail if the listing runs out of stock. When an item sells out, there is a delay in the "sales notification" from eBay's API to our system.
How to avoid the out of stock delay
Do not set eBay Quantity set to "1"
Instead, set eBay Quantity to high enough so that you won't sell out within 60 seconds.
Technical Note about eBay's delayed sales notification:
Sadly, we have verified with eBay that they are having some technical difficulties with their "notification system" in their API. If eBay experiences these difficulties, our system is not informed of the sale, which means we cannot restock the quantity automatically.
Because we aim to do everything in our abilities to make our system flawless, we are in the process of developing new methods for this feature that does not use eBay's "notification system." However, this will take time.