I didn’t find any answer to this, but after alot of searching and some fiddling I found a solution:
Google Play is installed and works as usual, BUT the CUBE application (which also runs some processes in the background) prevents it from accessing Google Play. So remove all CUBE applications, remove background running CUBE resource and programs (Settings->Apps->Running and Settings->Data usage). I also removed all the other Chinese apps.
When all Chinese stuff is gone -> Voilá, Google Play starts working as normal. 🙂
