This is a wholly sub-par cab service in every way imaginable. We called them twice the day before (because we needed a very early ride) to confirm, and they obviously made no record either time (different people answered the phone). Both simply said: ""Can you call tomorrow?"" as if we were bothering them. This was for a ride to the airport to catch a train that we couldn't miss: not some inconsequential cab ride, mind you.
The next morning we called again, and again no record of any previous calls, and nothing but attitude and incompetence. Wouldn't send a cab that early because ""we only have five cabs, and they're not ready"" a detail which would have been quite valuable the day before, when we could have made other plans.
The short of it - we missed our flight and had to pay $1,500 for new tickets (the next flight would have missed the train). Talking to the Yellow Cab manager was akin to trying to communicate with an irate and defensive child. He had no apology or remedy: only so much puerile drivel to heap upon the already costly and horrid experience.
So, avoid Yellow Cab Roanoke at all costs. Call a friend, ride a bike, walk if you have to. Just don't rely on these hacks for anything.