MrHard - 11:47 pm on Nov 9, 2010 (gmt 0)
Mastercard/Visa can AVS on address and zip. Gateway issue? or are you using PayPal?
You can check phone easily on your own as well as ip, but irrelevant as far as a chargeback is concerned.
Btw, for customers purchasing over $1k if you have to do a conference call for any reason you are going to be losing more orders then if you just put it through.