Contact names not showing in sms iphone 4s

I use Exchange from google to get my contacts. Everything has been fine except today I get a text message and it shows the phone number, not the name. Also, when I text someone from my contact list, I get their text in a different thread with just the phone number, not that persons name. This doesn't happen in imessage fortunately, just regular sms. This same problem happened to my friend, and she hard reset her phone by pressing the home and lock button. I did the same thing, but it didn't work.

SOME ONE PLEASE HELP ME!!!