It says you got it for 6 mil though, which matched his max bid amount for the letter. Unless they just gave it to you for his max bid cause you were willing to bid more...I got nothin D:
Otherwise...there's always the option of beating it out of you with the hammer
Edit: I should note that giving it to him for Zero's max bid is a bit...weird :x Shouldn't you use the next increment up in that case?