No worse feeling than an unhappy customer...since you don't have the money to refund her, offer her a set of cookies for a future order - maybe for Thanksgiving...since sugar cookies aren't your norm, maybe offer to do a sugar cookie for her as an alternative that she might like...I would give her the absolute best customer service EVER...since just like Julia said, bad news travels FAST! You don't need any bad PR. So sorry that you are going through this...it really is a miserable feeling, but just remember, for every bad customer you have, there will most likely be 200 happy & fantastic ones...Don't let this get you down and steal your joy.