Samsung galaxy S2 plus i9105 - phonebook problem

[Gabi84]

Hello.
I have an issue with my device and i hope that somebody can help.
From time to time, that means around each two days, my phone forgets the entire phonebook and does not show any contacts at all. If i restart the device, it works again perfectly. This is rather disturbing because i do not see it each time and if somebody calls me, i see it like a normal number that calls me, it does not show the name of the contact. Besides that, it always forgets my favorite contacts list and i have to redefine it every time.
Thank you.

 

[Pedja Medic]

Hello everyone I have a problem with calls,the moment I press green button to make it, display goes off and I can not do nothing, but call continue and I have to wait to person who I call cut call. Thanks for help.