Thanks for contacting us and so sorry for inconvenience caused.
Would you please provide more information to help get solution?
1. What have you performed on the phone before the problem happened? Do you rooted the phone or install any apps? Or did you over charge the phone? It could probably be operation system issue.
2. Could you still call your F2 or when you turn on, you could feel the vibration? If yes, it may be touch panel issue.
It would be better if you could bring your phone to our service center in your city. Please get more info in the website below: