Expanded Credit Capabilities (ECC) allows you to process refunds for transactions that either occurred over 180 days ago or were not processed through the payment gateway. While expanding your refund capabilities, please note that having ECC as a part of your payment gateway account increases your exposure to possible fraud.
When enabled for the Expanded Credit Capabilities, all credit transactions processed through your payment gateway account will bypass the referential checks in the payment gateway's Credit-Return feature and anyone with sufficient permissions will be able to issue credits to consumer credit cards or bank accounts without the following limitations that have been placed on other merchant payment gateway accounts: 1) credits may only be issued with a valid transaction ID against a transaction settled through your payment gateway account to the same credit card type and number or bank account as the original debit transaction, and 2) the sum of all credits issued cannot exceed the amount of the original debit transaction.
Please note that Expanded Credit Capabilities are available only to merchants who submit credits via the Advanced Integration Method (AIM), the Simple Integration Method (SIM) transactions, or via the Virtual Terminal or Upload Transaction File features of the Merchant Interface
To apply for ECC, fill out and submit the form available at http://www.authorize.net/files/ecc.pdf.