VitalPBX Mobile is an application that is offered free of charge to all our VitalPBX customers.
This app is based on the UK development ( https://www.sessiontalk.co.uk/), currently it does not have the option to read phonebook through QR code.
To verify the audio problems we recommend you delete the App completely and install it again (this is to verify that you do not have old code). If after this you still have audio problems, please try to use another app to see if it works well.
Remember that with this new App it is not necessary to select the Push Notification option.
Also confirm that you are using Default PJSip Profile (Not webRTC).