I would like to suggest that you allow advertisers to put in a backup credit card in case there is a problem with the primary card. I've had 2 cases recently where my credit card was declined and all campaigns stopped. If this happens when I'm away on a trip, it's not good to have all campaigns stop for a period of time until I get back to a computer.
Allow for more than one credit card as an emergency backup (this will allow customers not to go offline).
...and we made it happen! Now, you can enter a backup credit card to help ensure continuous delivery of your ads, even if your primary card is declined. In the event that we're unable to process a payment on your primary credit card, we'll attempt your backup card. Only if both cards are declined will your ads stop running. So, you or your billing manager can finally rest easy when you go on vacation. ;)
Entering a backup card is simple -- you can do it right from the My Account tab of your account -- but if you want step by step instructions, you can find them here.
