You have to check and set APN on your device as below.
1) Setting -> Wireless & Networks -> Mobile Networks -> Access point Names
2) Create New APN-> Input 3gnet in Name & APN Column -> Save
3) Back -> Select 3gnet -> Back -> Switch on Data Roaming
1) Settings -> General -> Network -> Cellular Data Network
2) Input 3gnet in APN column under Cellular Data & Personal Hotspot
3) Back -> Switch on Data Roaming
Make sure to ON DATA ROAMING for facebook and google.