It looks like something changed in the new phone2go version. I'm on android 7.1.2 phone2go version 1.3.1 build 30.
The app is running but not getting incoming calls. On the system notification bar it says phone2go connected.
In the app menu (above contacts) it has my name, previous versions had a green dot on the icon. pressing my name gets me to "my profile" where I can only edit my profile. In previous versions I could set the app as available but that is gone.
Sorry for the issues you are having with the app. Typically, deleting and reinstalling the app will resolve most issues. If it does not, please let us know.