Within ecomdash, you have the ability to use eBay's out of stock control for your listings:
1. Navigate to Administration
2. Choose 'Storefronts' and click into your eBay storefront
3. Choose the checkbox for 'Use eBay out of stock control'
This will allow your listing to reach a quantity of 0 without ending the listing on eBay. When the quantity reaches 0, the listing will become 'unavailable for sale'. Once you add quantity back in ecomdash, we will sync a new balance and make this listing available for sale again.