I’m unsure how to answer the statement, which is written with a question mark.

While I’ve moved on from my PLAYBARs, the volume control should not be disappearing, in either the S1 controller, or the S2 controller, on any device you’re running the controller on, much less the PLAYBAR disappearing. If I am interpreting your post correctly, it suggests a network issue with a connection dropping between the PLAYBAR and your router. It isn’t clear whether your PLAYBAR is wired directly to your router with an Ethernet cable, or wirelessly connected to your network in some other way. Which leads to two potentials, either wifi interference , or possibly a duplicate IP address issue. Much of the former is covered by the linked FAQ, I’d encourage you to read that. If it could be the latter, I’d recommend unplugging your Sonos devices from power, and rebooting your router. Once the router has recovered, power back on your Sonos devices. This will give them both a fresh IP address, as well as a refresh of the Sonos OS. Finally, check your system for updates, in case there are any that need to be applied. 

If neither of these potential solutions work, I’d recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. But don’t post the resulting diagnostic number here, they get sensitive about GDPR.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

There is nothing I can do to help your emotional state. 

Make sure that PLABAR and the controller are up to date.