When we bought our cottage, the "phone company" charged about $40 / month, year-round and the quality was pretty poor. I tried a VoIP service available through my computer but wasn't too happy with the quality of the connections, especially on business calls.
When Vonage became available, I decided to try that. They provided the "box" that connects to your router and your phone(s). for under $20 / month I get 500 minutes of local and long distance, voice mail (printed out in an email), call forwarding, and a bunch of other stuff. When my Internet is down, calls automatically forward to my cell phone. I liked it so well, that I ditched the phone company at home and got the unlimited plan. A couple years ago, I got my mother switched over.
They have changed their interface box to make it even easier to set up. One of the problems with VoIP is that it relies on a steady stream of small packets, sent in real-time. Buffering is not an option. Dropped packets mean moments of silence. There are ways to give VoIP packets priority, but you need to configure your router. Vonage's new approach is that their box plugs into your cable modem and your router plugs into the Vonage box. Voice traffic automatically gets priority.
They also have a smart-phone app that allows you to make cell phone calls via a WiFi network. Such calls use no "minutes" and domestic and global long distance is free. You do consume some of your phone's data allowance, but not much.
Anyway, I have troubles with lots of things (cable, Internet, cell phones) but Vonage isn't one of them.
[I didn't mean to write so much, but I went on Medicare 2 days ago, and I now feel entitled to ramble on
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