Zoom Phone - Poly Handset

Hey everyone! We have some of the Poly phone handsets to accompany our Zoom phone and I wasn't sure if you guys had encountered the following issues and/or if anyone has a workaround! We've found that when you change the outbound caller ID in the Zoom client, the phone still won't make calls out from that number, even after resetting and seems bound by whatever settings it was given upon initial setup. Another thing we can't seem to figure out is how to transfer directly to a voicemail from the handset? All of these processes are so straight-forward in the Zoom client/web app, but not on the hardware! Any insight at all is very much appreciated!