A few of related notes, worth mentioning:
* Because there are a vast number of servers that must update each change you make in your account, it is wise to anticipate a delay, which might range from a few minutes to a few hours, depending on traffic. So if you were to delete now it will take a short time for your ads to actually stop running completely.
* Because stats run about three hours behind, if you were to delete now, you'd still see stats come in for a few hours. These will be impressions and click that occurred before you deleted your ads.
* With AdWords, one is billed after the clicks have occurred, rather than before. So it is an expected behavior that after deleting one's campaigns there'll usually be a follow up billing. This billing will cover the period from the previous billing, to the time that the campaigns were stopped.
AWA