hrm, sounds like you did everything about right.

What was the voltage you ended up storing them at, and what voltage were they at when you got back to them?

The thing you can do is try reforming them. That means a 0.5C charge and a 2C discharge for 3 to 5 cycles and see what that does. Maybe that would wake them up. Other than that I couldn't really guess what happened to them unless they were cheap packs or got too hot.

hopefully that helps =)