The application does have the ability to have audio, one way or two way.
If it is not working please check the following settings:
On your devices has sound been accidentally disabled for Presence. iOS 9& 8, differs from iOS 6 & 7 but you should be able to confirm finding Presence in your device Settings pages and confirming that the microphone is allowed.
Other things that can help:
Sometimes signing out and back in fixes the problem.
If not, could you check a few audio settings on your Presence camera and viewer?
*In the app, when you're viewing your camera, go to Options and make sure "Allow Microphone" is turned ON. Try flipping it off and back on again too.
* Make sure your volume is turned up on the phone.
You'll know you have it working when you go into the same room as your camera, view it with a phone, and you hear audio reverb/echoes.
This usually is very effective.
[iOS] Soft reset devices:
Keeps all of your data but cleans out your device. https://www.youtube.com/watch?v=j0Tlmsx2ETM