I updated my Lumia 640 Windows Phone, after update was completed I saw that all my contacts and my texts were gone. I tried to retrieve them by restarting my phone but this did not work. Is there a way I can get them back?
Do you still have your account attached to the phone? Go into settings, then to accounts, then to Email & app accounts (this is in 15063, if you're on an older version of W10M it might be different).
Once there, you should see the Microsoft account you log in with on your phone. If it's not there then tap Add an account and add your Microsoft account. After a while your contacts will get pulled down and all of your text will slowly get pulled back down again, too.
I've seen this happen quite a bit on the most recent build. I used to have a Google account added to the phone too, which I used solely for my older contacts, but since I stopped adding that account whenever that happened, it's seemed to have stopped happening.
Let us know how you get on with this.