Hi
Thank you for your question and sorry it took so long to answer!
Current version of plugin only deletes those ads that are returned from API in sold state. This means that to remove the product from WC the process has to be following:
1. Set product to sold state in NettiX
2. Wait plugin to sync and remove products that are NOT in “forsale” state
3. Remove product from NettiX
I have improvement to this in roadmap but it won’t be implemented until in 2.0 version of the plugin which should be coming during year 2024.