Turn off Wifi.
Go into "Settings"
Turn OFF Wi-Fi
Turn off iMessage
Turn off FaceTime
Go into "Settings"
Find and enter the "General" Tab
Scroll Down and enter the "Reset" tab
Click on the "Reset Network Settings"
It may or may not ask you for a password, just use the same password again you use to get into your iPhone
After you pressed "Reset Network Settings" Your phone should have automatically restarted.
NOTE: DO NOT SIGN INTO WIFI, From now on until your "iMessages/Facetime" Works, You should be running on "3g or 4g" internet