This was a lose-lose situation for you. Regardless of your decision, she would not have been happy with it.
Personally, I would not have not been upset that you had saved me $$$.
Only suggestion that I can think of is to ask for a phone # in the checkout process. Many places ask for this. If you had had it you could have called. I know that an international call could have been a little expensive, but ultimately you would have had a happy customer and not held the order open for weeks.