Why won't the upgrade coupon I was given for Mountain Lion work?

Episode 901 (1:20:25)

Debbie from San Diego, CA

Debbie bought a Mac Pro and was given an upgrade coupon for OS X Mountain Lion, but the upgrade code keeps getting rejected. Debbie found out that someone in Japan had taken the number, but Apple wouldn't give her another upgrade number.

She was concerned about her online security since someone had gotten that upgrade key, but Leo said it was just a lucky guess that someone came up with her upgrade key. Debbie's biggest problem is from Cupertino at this point. She should go to the Apple Store and talk to a Genius. He has a hunch they'll fix it.