I just bought the premium version of the game and created this forum account. I see that you can link your account to your profile to show you're a premium member by uploading your product key which is a file with a .amk file format.
I'm on android, where can I find that file?
Find User here you can look for a user
Where can I find my .amk file?
#1 2017-09-08 19:07:00
#2 2017-09-09 11:35:22
Send an email to email@example.com from the email address you use for your Google Play account and explain that you purchased the game on Android and would like the multi-platform key. Be patient. It can take some time for the key to be emailed to you.