Basically, just always make sure that you are saving your game to Google Play. Any time you are putting the game on a device, make sure that you have logged into the same Google Play account. You can play the same account on different devices, as long as they all save to the same Google Play account. It happened to me, and I have heard a couple others mention that it takes a bit of time for their account to be recognized by Game Center. I imagine it could be the same for Google Play. (Personally, I attributed it to my old, slow phone…)
If you are giving advice to your alliance, I’d also recommend these few instructions as a ‘just in case’ for them. I posted them to my alliance after one of my players had to go through the recovery process.
take a screenshot or save your account number somewhere. It’s on the screen when the game is loading.
Connect your account to Facebook. * This does not save your account! *However, if a recovery is ever required, connecting a new account allows SG to more easily verify that the account is yours. They can take your old account and dump it into the new account you create that is linked to the same Facebook id. (other verification may still be required, but this really expedites things.)
Make sure you are saved to Game Center, or Google Play.
This is how game progress is saved.
In the game menu in Options > Settings you should see something at the bottom for save your game across devices. There should be something there that indicates whether or not your account is signed in to Game Center or Google Play. If you are uncertain on how to save to Game Center or Google Play, please check out Small Giant’s Quick Help and FAQ.