Advertising often speaks to a companies more subjective qualities like customer service. They're paying for it, so they can generally say what they want. Even if they are the only ones that feel that way about themselves.
Here are a few examples:
Not long ago, DHL ran a series of commercials that focused on their apparent ability to put "customer service back in the shipping business". You can watch one of these commercials below.
The public may disagree with DHL's take on their own service. They rate a miserable 1 star (out of 5) for customer service on Epinions. Read the full review here.
It's pretty hard to get a smile from an American Airlines employee these days. I'm traveling on American Airlines today and I've tried all the standard techniques like smiling, saying "hello", being a customer, you name it. There have been a few kind people, but overall hey seem a bit preoccupied. (Their Epinions rating is 3 stars out of 5.)
This reality didn't stop the editor of their in-flight magazine from writing about "service with a smile" in the latest issue of American Way magazine. You can read for yourself (page 12 of the magazine, page 14 in the reader).
There's a lot of reasons why customers may experience something different than the marketing message. Perhaps the clearest indicator is when there is no deliberate connection made between the message and the action. Employees don't know what's expected, don't receive training, and may not even know about the marketing message itself. Supervisors don't incorporate the message into their supervision. Management doesn't manage or measure how well they deliver to the message. And so on.