What do you do...you know if you back out she likely wont fuck with you no more or put you on a DNS list. In this case you have 2 options... 1.) Tell her you have Diaharrea or whatever and cant meet or 2.) go see her and drop off the donation (as long as its not pornstar type money)

In this case giving her your donation and apologizing seems to be the best choice. ;-( Lie about it being a back injury or migraine...never admit to Explosive Diahrrea. lol