Streaming volume control in Jabra Enhance Pro 30

I have been using my new Jabra HAs for a couple of months and searched their user “guides” until I found this site. I finally read that settings under Android Bluetooth connections are the wrong way to pair and connect - it must be done through the EnhancePro app.

Now finally, I can get my phone to ring in my ear. However, when I want to hear voice mail there is no volume control, in spite of the instructions to use the buttons on the side of my phone.

Any advice, ideas and suggestions greatly appreciated.