This happened to me also so I called Voipo, here is their response. "The call was from your number, and your device, but whoever made the call dialed *67 before dialing the number (##########). When you dial *67 before a number it marks your call as private. Instead of actually sending the call as private (as these types of calls are often blocked) we will use a false number, which is the 4049535888. It does not link back to yours or any account, so whoever you wanted to call privately cannot see your true number or call you back since that is the only number they'll see." Soooooooo. you probably used *67 before making the call and Voipo used 404-953-5888 as a number the person you call will see.
This is a scam to collect false debt , they claim you owe them money for services that don't exist, and they claim they have a recording of you from 2 years back. BEWARE