This isn't a gaming forum per se and most people here will have no direct experience with your game. I've never heard of it and don't know why the game would even need a link to a Facebook account anyway? You'd surely get more replies if you searched for the game's support forum or thread.
Or in the alternative a forum catering to game enthusiasts of games similar to this one. I'd urge you to try that as it would be by far your most effective way to get peer to peer support from people who are actually familiar with your game.
You did mention that you'd contacted "King". You didn't explain who that was, but you probably meant the game developer's support. Perhaps try that a second time in case your original request got buried or misdirected. And you might want to see if they have a support forum or IRC channel that might provide more timely replies than email.
As a generic attempt to resolve your game issue.. you said that you tried clearing "the cache". Did you mean the system cache from recovery mode? You should also try wiping the game cache and "data" from the Application manager inside the Settings menu. And failing that, also try uninstalling, then reinstall the game on your phone. Those two things have a reasonable chance of succeeding.