I would say, "Well sir, I have spoken to one of my "contacts" in Dell and he has agreed to discretly send me a modem, It should only take 10 mins at the most to install. Then I would appologize for wasting all that time trying to fix a broken modem that was under warranty. Then install it free of charge to keep him happy, so he hopefully mentions you to his friends"

Then I would bow my head (in shame) and make a hastey exit!