We had three orders from a customer using a stolen credit card.  We had shipped the orders to an address that didn't match the billing address and as a result we had to take the loss when the REAL credit card holder had the charges reversed.

I went into VeriSign and changed some settings.  We now require the CSC code and we require an AVS match.  (AVS= Address Verification System)

The problem is that we are now getting about 1 in 10 customers saying "Your system keeps rejecting my credit card".  The VeriSign settings on the AVS had options of high, medium and low).  I changed it to "low" and we still get about 1 in 10 customers saying "Your system keeps rejecting my card".  Anyone else deal with this? What else should I do for security?