hi i have iphone5 i have problem with facetime and imessage activation it says activation unsuccessful

Not enough information.

What country are you in and what carrier are you using?

Facetime uses an international SMS message to activate with Apple's servers in the UK. If you are not using a supported carrier, you must have a plan that allows internations SMS messaging and the carrier must process the messages correctly or activation will not work.

iMessage and Facetime use SMS messages to activate. Talk to your carrier. All supported carriers in countries where these features are not banned by law will allow the activation SMS messages to pass to Apple in the UK.

There are no supported carriers in Oman. The iPhone is not available from any authorized source in Oman.