If you don’t see them in favourites try reinstalling the app. 

Use the desktop app, or third party. Your playlists are still there, its just the mobile app can’t display them reliably.

hi Bumper have tried reinstall still all gone!

Controlav - ok desktop app has my playlists.

Whilst some relief as they contain our Wedding Day playlist, which took weeks to compile , and as a collective are my complete music collection, I need them on my phone app which is convenient and easily accessible - the point of the app in the first place! Thanks for your help in locating.

You can save the playlists to your phone with Phonos Plus ($1). Then use a web service like Soundiiz or similar to convert the playlist to whatever music service you use or edit for local library.

https://apps.apple.com/us/app/phonos-plus/id1511326524

https://support.soundiiz.com/hc/en-us/articles/360018717099-Export-Sonos-playlists-and-transfer-them-with-Soundiiz

Have a backup plan for sound if you use Sonos for music at your wedding, wireless systems can stop working at the worst times.

But Congratulations on your wedding