Do your self a big favor and do not use Authorize dot net to transact your cards. Eventually you will wind up with problems and it will cost you.

In there very own words to me during a phone conversation after they conducted several fraudulent credit card transactions that cost me dearly in fees etc.

I quote "You don't understand, we don't authorize credit card transaction, we only transport numbers from one place to another. You have to check the transaction, it is you responsibility to verify whether or not the card is valid."

One of the fraudulent cards that they had authorized was used with a 00/00 expiration date.

Always remember that banks, governments and corporations do not have your interest at heart.