If you're experiencing an issue that doesn't allow you to reach Settings in-game, in order for the support team to find your account please provide your UID (short for User ID).
While the game is loading, watch the top left corner.
Your UID will populate once the game is almost fully loaded:
Alternatively you can also tap a few times on the band stage on that loading screen and that will pop-up information the support team can use as well.