There are a few instances when the data sync may not work:
1) Different OS:
If one device is an Android and the other is an iPhone/iPad, it is not possible to transfer the data.
2) Different ID:
If your new device is not signed in with the same Google Play ID, the app may not be able to find the progress from your other phone.
3) More than 2 devices:
If you own 3 devices, and you're signed in with the same ID in all three devices, only the data from last played device is saved to the cloud. In this case, you should win at least one game from the device (with the data you want) to save it to the cloud.
If none of these apply to you, please send us a ticket through the HELP button in Game Settings.