I can't save new numbers in "people" app

[Niloofar6]

HELP! Every new number I save, goes unsaved again after a while! All my contacts are the ones I have saved before this problem occurred.
In some cases if the number has a whatsapp account, It's whatsapp information remains but the phone number is gone

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[Niloofar6]

And reset factory didn't fix the problem. I was hoping it would be fixed after lollipop update but it's not. Any ideas?

Sent from my Nexus 4 using AC Forums mobile app