Hi,
I got Volla phone about a week ago. So far, impression is mostly positive, I got the most important stuff set up (CalDAV, CardDAV, my core apps) but there are few issues.
One of them is: When the phone is ringing, it's showing number instead of the contact name. I haven't been able to confirm but I think this does not happen for all contacts. Anyway, it happens repeatedly for a certain contact --- and I'm sure that the contact is in my contact storage -- when I look at the call log, the same call shows properly!
I went to Permission Manager and checked that Phone and Dialer both have access to Contacts, so I don't know what else could be wrong.