1. Repricer (that runs every 20 minutes) relists an item (if it was ended, but supplier got back in stock)

1.5. Repricer gets all items that should have been relisted, finds the new relisted id and updates database accordingly

2. Repricer updates internal Sku's database that the item is in stock now

.... some time has passed...

3. Ebay sync tool imports all of your ebay items into Sku and syncs stock information (every 3 hours)

4. Ebay sync tool checks all out of stock items if they were relisted