Q: cellular data did not connect & ipad restart several times

Hello asif19,

The following article details steps that can be taken in order to restore your cellular data connection to your iPad.

iPad (Wi-Fi + Cellular Models): Troubleshooting a cellular data connection

http://support.apple.com/kb/TS4249

Resolution

Follow the steps below, testing after each step.

1. Update your iPad.
2. Toggle the Cellular Data setting off and on under Settings > Cellular Data.
3. Restart your iPad.
4. Check for a carrier settings update.
5. If your SIM card has SIM PIN enabled, try turning it off: Tap Settings > Cellular Data > SIM PIN.
6. Make sure you're in an area of good coverage. If the cellular data connection works in another area, contact your carrier to report the original affected area.
7. Reset network settings: Tap Settings > General > Reset > Reset Network Settings.
8. Restore the iPad as new.

If none of the above steps resolves the issue, make an appointment at an Apple Retail Store, contact your carrier, orcontact AppleCare to troubleshoot further.

Cheers,

Allen