6s can't make or receive phone calls. Everything else works.
Hello,
So, I bought a 6s last week. Used my old sim from my 5 and everything was going good up until noon yesterday. I was making and receiving phone calls in the morning, and now suddenly, and into today, I can text, e-mail, browse social media, but can not make or receive phone calls. Any idea as to why? I have at&t, and before I go there, I am looking for some help. Thank you.
iPhone 6s, iOS 9.0.2