I just bought myself a new Iphone4, it’s good and was working quite well. But over the course of several days, I am getting texts from different numbers of people I don’t know, numbers I’ve never seen, asking me, “Who is this?” They all say I’ve texted them, even though my message history shows that I never did. Is my phone doing this on its own? Is there any way I can stop this as soon as possible. If any suggestion, please help.