My iPhone 5 will not complete calls, phone will ring but only dead air.

In the past few days (since the last software update), my iPhone 5 has stopped working for phone calls. I can do everything else, but calls will not go through. If I call out, I do not hear a ring on my phone, but it will ring through on the recipient's phone, but we will both have dead air when it is answered. If someone calls me, my phone will ring, but when I answer it, it is nothing but dead air.

I have already tried the following:

- Turn airplane mode on, wait a little bit and turn it off.

- Took the SIM card tray out and put it back in.

- Held the lock and home buttons until the phone switches off, wait a little bit, and turn it back on.

- Reset the Network Settings.

- Phone has been cut off overnight more than once.

Any suggestions?