I am playing about two weeks, and shop was closed from the beginning. I tried all the suggested steps that I could find: finishing account setup, changing password, re-login and wait for 10 minutes, clearing cash/data(a lot of times), made a factory reset to unroot the device(although I didn’t root it and root checker showed abscence of root). In the end, game masters said there is nothing else I can do and suggested to leave a bug report about unknown issue. Guess spending gold on another device is the only way. 
did you update the game to the latest version? (there was a new patch for pc last night)
Yes, I did. And I am writing because it opened! I am sure nothing have changed with my phone. So, probably moderators have read this post and fixed it. Thank you guys)