My iPhone is not letting me make phone calls or send text messages?

It was working just fine all day then suddenly it malfunctioned. Whenever I am trying to call anyone, it is suddenly hanging up the call and is saying "call failed" and when I am trying to send text messages, they are not going through. The Internet is working just fine.

Why is this happening? Is it a service problem? I am with Fido. Or is the phone going haywire? It's an iPhone 4S. I've never had an issue like this before. My first time ever. I am up to date with my phone payments too.

Same im on rogers its nation wide in Canada and text me

Rogers and Fido are out Canada wide. Search on a search engine, it will come up. Millions without Celluar Service.