Sound in app disappears after going to Control Center

Help?! When we got the iPad2 we noticed that our app loses sound when you swipe to go to the Control Center. If someone starts the app and thinks, "Hmmm.....I want to turn the sound up", swipes to the Control Center to change the volume, and swipes it away, the app is now silent. It doesn't even matter if you change the sound. Just swipe to Control Center and swipe back....no more sound. The only way to get sound back is to leave the app and get back in. And, since the whole point of the app (tAPPy baby) is to make noise, it's really not good :-(

Any ideas what happened and how to fix it?

Thank you so much!

Anyone? Thanks again.