It's all about your approach dude. Sometimes the most honest approach is the best, find some testimonials from other people saying how much Hibu sucks, and then tell them how you can do it better. If you have a big list, you have nice potential to experiment. See how well a certain pitch works for 10-50 people and then improve based on that. You have nothing to lose but time.
Ardley, how did you approach the customer. Cold Call? Email?