From what I recall, Velocity uses DSL equipment owned by Sonic, but co-located in the AT&T central office (using wires belonging to AT&T, hence their charges). So they only offer the service in places where Sonic has such equipment installed. You are lucky you have the option, I don't here in Ben Lomond.
The only actual land line phones go to AT&T. I think even in your case, the wire to your house is AT&T, and the connection to the phone system is in the AT&T central office, and probably drops right into the AT&T phone switch right there. Velocity taps off the data channels and routes your internet separately.
So in reality, if you want a real, old fashioned land line, it's AT&T. I also keep one for emergencies. But so few people are left with landlines, the cost is getting excessive. $50/month is what I'm paying.
For internet, Cruzio has a number of technologies, which may or may not be available in your location. Sounds like you are on the least useful option. One step down is me, where they don't offer any service. If you can get fiber, or their point to point microwave links, the service is great, but those depend on where you are. Comcast is the fall back most everyone ended up on. Other than some niche players (Starlink, satellite dish, some radio link options), those are your options around here.