missing option in comcast business app to listen to voice mail or make calls on android

I installed the comcast business app on my android phone yesterday.  At that time there were multiple options on the bottom of the screen.  Home, Accounts, Phone, TV and Settings.  I was able to make calls check voice mail etc...  A couple hours later the phone button disappeared.  I rebooted phone.  The phone tab reappeared.  Today the phone tab dissapeared again.  I rebooted phone.  Still no phone tab.  I uninstalled the app.  Rebooted phone.  Reinstalled app.  Still no phone tab.  Also when it was working the voicemail volume was barely audible.  If i put it on speakerphone i could hear it barely.  With speakerphone off i could not hear the message at all on my phone.  App version is 3.0.9