We recently updated my mother-in-law's phone and had the contact list transferred at a Verizon store. We later learned that one of her contacts was being sent directly to her voicemail even though her phone was on she wasn't talking to anyone else. We noticed when that contact called, her phone would briefly display her name and then would display the Verizon logo like it had reset. Tech support couldn't help me and tried to forward my support call to someone else, but all the support lines were busy and I got tired of waiting on hold.
The solution we came up with was to delete that contact info and then re-enter it. That solved the problem. Evidently there was some glitch in the data when the contact list was transferred.