2008: the year of chargebacks/disputes?

Hi,

I would like to hear from other merchants if their visitors' shopping behavior changed in 2008 compared to past years.

Our online store has average of  2500 orders per month (25% increase comparing to last year). Last year, we used to get average of 1 dispute/chargeback per month due to fraud or other reasons. I would expect that number increased to 1.25 or even 2, but it is more than quadrupled.

If the billing and shipping addresses on the order are different, the claim usually goes like "I haven't ordered such thing". We lose, case closed. If both the billing and shipping addresses are the same the claim is "We never received the goods". Even if USPS tracking showing it as "delivered" we cannot prove unless there is a signature.