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This seems to be a common occurence after updating, the same thing happened with 9 and 13 updates. I was going to recommend texting WEB to 40127 to download the carrier settings and synchronising to your itunes account.
I have also done some searching for you and found the link below, it has some extra easy fixes for you to try.
Hi Ann. Thanks for the reply but I've already tried all these fixes and none of them work. Even did a factory reset which was a waste of time too. Think I'm gonna have to go into an apple store & get someone to sort it.
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