Go back to Best Buy and call the police. A crime has occurred and you are the victim.
Calmly explain that that is what you have to do with the BB manager. If that doesn't work ask for regional manager. Calmly explain that if you were a thief you would not be calling the police. Explain you intend to call the local news media who would love to report on this during the release of the iPad 2.
If you paid by CC explain you will call bank and demand a chargeback.
Explain by not following up with the original "purchaser" (thief) they are allowing the crime to go unpunished.
Explain that if all else fails you will be filing complaints with your state's Attorney General, local congressional representative, consumer affairs, better business bureau, social networking, and any others you can think of.
Don't give up.