Booked online for an 8:15 a.m. ride to the airport.  The site gave me a confirmation number.  At 8:18 a.m., we called in, and an automated message said a cab had been assigned and was on its way.  At 8:30 a.m., we called in again and noticed that the automated message said that \"cab zero\" was assigned, which didn't sound good, so we spoke with a human who said that the online submission had not specified a regular or special cab.  I was pretty sure I had specified \"regular cab\"--but if there was some uncertainty, why not call me at the phone number provided, before the time I was expecting a ride?  We ended up having to drive to the airport and park in short-term parking for a week in order to catch our flight.  Discount Cab, by contrast, has always shown up reliably on time when booked via their website, and I will use them from now on.