Hey Mike,
By your pic's, info, & correspondense to the seller & his remarks, it sure sounds like you are honest & a man of principal. The pic's are compelling as the dampener looks beaten like a red head step child. If it were me, I would want to be the first person to lighten a flex plate... I would want the oppertunity to choose the area, how much material I remove, & where I do it. More importantly, I would want to know that it is done by someone else first BEFORE I purchase it.
Gonyea, being that there is a accurate story documented w/ proof (pictures) & correspondence of this transaction, my opinion is that you should refund. Not saying you Scammed Mike, but this is not what Mike expected or wanted. The honorable thing would be to make amends & reverse this deal. JMO!