re: Need advice from an IT baw re Phone Options for Sales Call Center...

You should have a local ILEC in the area. Basically that's your local telephone company. They are the ones who usually will wire up telephone jacks. That may not be Spectrum which is why they don't do that anymore.It sounds like the tech's "Toner" wasn't working and that does complicate things when trying to locate phone lines. It's basically a tone generator.

That being said VoIP is probably your best option. You'll need network drops everywhere you want a phone. You'll need to find a provider. Spectrum may even do this, I'm not sure. A-lot of times they can setup an auto attendant for you pretty easily. Without you having to have a local PBX. Which is probably what you want. Getting VoIP working right on your network can be tricky sometimes, but it's common enough now that pretty much anybody in IT is dealing with VoIP now.