IPhone 4 not getting incoming or outgoing calls! Help?

I have sprint & everything else is working just fine! I can't dial out. My family said there calling my phone but its not coming through. Please help sprint couldn't

That happened to me but all i did was restart it and it started working try that if you havent, you can also try to restore it with a computer

Restart the iPhone by holding the CIRCLE AND POWER button UNTIL YOU SEE THE APPLE LOGO. DO not let go when the screen blanks, you must keep holding both buttons until you see the Apple logo.

Hi. Try turning the phone off and removing the sim card.