App Is NOT Working!!!!

Okay, so I was part of your Beta testing for this app and it functioned properly until two weeks ago. Now I cannot make or receive calls from the app, sometimes I cannot even sign in on my iPhone 6plus. This is a complete nuisance as I expect to be able to conduct business on the go with what is supposed to be a mobile app. Now I am missing important phone calls and this a hindering my business. I thought you guys got it right...I guess not.
I absolutely need this app to function exactly the way it should without further delay. I really hope your developers are making it a top priority to fix this app ASAP, please dont take much longer or I will have to take my business elsewhere.

BrooklynMommyOf3 about Vonage Business Communications