My sim card its not working

I hope someone can help me.
I have iPhone 4 and I updated it with the newest version 5.1 so now my sim card its not working. NO SERVICE. So now i can't text and call!

Sometimes sim cards do that when it looses the connection with a satellite. If you turn it off and on again it usually fixes itself.

You can contact your customer service centre. If they give you unsatisfactory answers, you better change your sim card.