Well, first: the receptionist is a fawking idiot! Why would you ask the receptionsist anyhow? Is she going to fix it for you too? Go talk to the service manager.
I had the same issue on my 03 H2 and my 05 SUT, The vent tube to the tank was the issue both times along with some sensor that was replaced in the tank on the 05. It's a fairly easy fix and was covered under warranty. The later took a day to get fixed.