New iphone 6 3G working but cant make reciveve calls
I have a brand new Iphone6 64GB out of the box, restored the Iphone5 back up and inserted sim card. All works perfect except the network carrier is regonised in my case Tesco(o2) and 3G is working for data no problem web and email, but the phone signal shows 5 empty circles and I can't make or recieve calls.
HELP PLEASE
iPhone 6, iOS 8.1.3, New out the box