Have you tried a long press shutdown.  You have to press the power button for over 7 seconds .

Are you sure that it has the full battery? Try to charge it again for 15-20 minutes

It is possible to check the Roams battery via the web interface too - goto this address using a web browser and see if all looks okay:

http:///iP Address of Roam]:1400/status/batterystatus

If the issue persists, then try this…

• Whist ‘off’ it’s charger (that’s important) with the device powered ‘on’ - press and hold the rear power-button. The Roam will power itself off after approx. 5-6 seconds, but do not let go the button, keep it pressed for about another 15+ seconds until you see the front top status LED (near Sonos logo) light-up and glow white and then place the Roam back on its USB-C charger (5V/2A (10W) PD power supply minimum) and leave it until it’s fully charged (check via the web interface) - when it’s reached 100% it should then be okay after that.

Hope that suggestion assists.