We called United, which is a service provider we've used in the past to comply with our county's requirement that our mound system be pumped biannually.  We scheduled a date and time for them to come, but on that date, despite his efforts, the driver couldn't get his truck to us because of all the ice. (We've had a very harsh and long winter.)  We rescheduled the appointment, hoping that the weather would break.  Three days before the rescheduled date, United called and asked whether it would be okay for them to come that day -- we experienced one day of above-freezing temperatures, and they wanted to give our driveway another try.  They came soon after they called and completed the job quickly and professionally.  And they didn't charge us anything extra for the first unsuccessful trip.  We'll definitely use them again.