joined:June 14, 2003
I ran into a double billing issue with adwords recently.
My CC was declined for a payment.
A day or two later, I went to make a manual payment for the amount that had been declined, and then was billed twice the amount.
The bug is with the automated billing retry payment system, that doesn't account for manual payments, and rebills missed payments as soon as a valid credit card is available.
Customer service is also unhelpful with the issue, and refused to credit the duplicate payment.
Between the two effects, it leads to a very unpleasant customer experience.