I just received an iPhone 5 to replace a malfunctioning one. I transferred my sim card, but It appears as if my phone number did not make it. No one can call me. When I try to access voice mail it acts as if the request is coming from another number. I am ancient and the Iphone world is fairly new to me. I do not have cell internet access and use wifi from my home router for things like downloading apps. Any assistance would be greatly appreciated.