Some updates: that same day I called the boss personally. Told her about all the problems and asked if i could exchange. She told me to bring the phone to let her check first. I did not waste a single minute, straight went to the service center to take my phone, and went to see the boss.

She told me, it may be the 3rd party softwares (games which her worker put in). after she deleted it, she told me to try another day (surprisingly the screen can on normally). I tried to switch on and off few more times until finally it suddenly can't on again.

Finally she changed the whole set for me. So, now I have a new set. But, if it's Garmin + mini opera, it is still the same thing. So, finally I deleted Garmin and so far it works perfectly fine.