My iPhone 4S will not making outgoing calls.

iPhone 4S will not making outgoing calls. I don't know if I can get calls or not, but outgoing calls are a no go. It stays stuck on "calling" and never connects or says call failed. Can't even connect to voicemail, and all the messages I had saved are no longer listed on the voicemail screen. It's just blank, but I can't call voicemail manually because it won't connect. Texting seems to still work, sometimes. Occasionally, I'll get the "Message Send Failure" notice, but usually the texting works fine, even though the phone does not. I've restarted, rebooted, changed the date and time settings like I read somewhere, and nothing has worked. I'm running 5.1.1 and it is not jailbroken. Any ideas would be greatly appreciated! Thanks.