Phone companies are chronic offenders. They offer all kinds of deals to new customers, but if you're an existing customer, you get nothing. It's almost common knowledge now that the best way to have the best cell phone and the best service is to switch companies every 2 years!
I ran into another example in a less-likely-to-offend industry the other day: the hotel industry. I called on a Sunday looking for a conference room for the following day. The response I got: "There's no one here to take your reservation." HUH? Who am I talking to then? For them, they were so caught up in their internal departmental responsibilities that they couldn't take my reservation because no one from the catering department was working that day. Heck, they even recommended another hotel nearby for me to try.
Don't you think someone ought to be fired over that?
How hard is it to add the conference rooms to the booking software so that anyone can book any room?
Stop allowing your employees to invent ways to turn business away. Start inventing ways for your employees to build business.