You could have just been in a "dead spot" where service was spotty. Have you updated your phone's PRL (Preferred Roaming) lately? That might help. Dial *228, then option 2.
Both recent times, I have been in my home in north Ft Worth between Bailey Boswell and HWY 287. How can I find out where the Verizon Cell Towers are. There should be some out here. I'm south of Alliance Airport.
If your calls are automatically being routed to your voicemail, the issue may be with restrictions in your phone. If you've enabled any kind of call restrictions (i.e. setting incoming calls to "contacts only" through the phone's menu > settings and tools > security > restrictions > calls > incoming calls), anyone calling you that isn't saved in your contact list will be automatically routed to voicemail.
It may also be a coverage issue. There's a coverage map right here on the Verizon site. Hover your cursor above "Explore" at the top of the page, then select "Our Network and Coverage" to pull up the coverage map, which will allow you to enter an exact address in order to view your coverage in your local area.
Finally, the issue may also be related to call forwarding or immediate call forwarding. You can disable call forwarding yourself by dialing *73 from your phone. (It can be enabled by dialing *72, then after the confirmation beeps are heard, enter the ten digit number to forward the calls to).
If none of these solutions resolves your issue, I would recommend calling Customer Service by dialing *611 from your phone. I know that a lot of people dread calling those of us that work in Customer Service, but most of us are actually very kind and care about our customers. Just be good to us and we'll be good to you.