I randomly picked lots of numbers that say not available.
It makes it look like you have many rate centers and no stock.
(IA, FL, HI, MI tried.)

A bunch of dead ends is going to be frustrating to someone signing up.

Many will know locally, but struggle picking a virtual number.

Michigan/248 is too broad. Michigan/248/FARMINGTON(522) is better.

I see you that 248-522 is BROADWING COMMUNICATIONS, LLC - MI
Right now the live form has State - Ratecenter - Number.
We're moving to State - Area Code - Ratecenter - Number.

Right now the dev seems to be State - Area Code - Number
  • So in summary State - AREA CODE - Ratecenter(Exchange) - Number seems better.
  • I would gray-out unavailable Exchanges.
  • I would state that unavailable Exchanges can be special ordered.
  • If you can't supply Hawaii, why make it look like you offer it?