Updating item availability on the Swiggy merchant app, rather than through Foaps, may result in sold-out items being displayed on the Swiggy customer app. To resolve this issue, follow these steps:
1. Turn off all items from the Foaps menu.
2. Turn on the items that are currently available in the Foaps menu.
3. Click the Publish button.
This will resolve the issue. To prevent this from happening again, always update item availability through Foaps instead of the Swiggy merchant app.