Speak to person at door

I just installed the Ring Pro and am not able to speak to, only hear, the person at the door. Is there a switch or volume control to set? I'm seeing a number of other posts on the same matter and it seems to be a global problem. I was assuming it was an operator issue and perhaps there is a switch or setting I am missing.I don't understand how sending a video will help since there would be nothing to hear from the door.