In case you need to contact Customer Support, make sure you provide the User ID you are using in the game.
You need to press the settings cogwheel in the main page of the game:
Your User ID will be in the next page, also, with the version of the game:
You need to press the profile button in the bottom right of the main page:
Your User ID will be in the next page, with some profile information:
To find your longer ID, go to Settings and scroll down: