Does not work at all - w aste of money

We bought this, set it up on 2 phones and neither works. We have hundreds of apps and have been iPhone customers sicne the start, so we are not newbies. This app is supposed to hear the baby cry and call the other phone. We put it on, the baby cries very loudly and nothing happens. Whats up?

Johnmac--3-e04-ro4r about BabyPhone Deluxe (Baby Monitor)