As of June 2019 Authorize.Net has decided to tighten up their rules surrounding ECC support, which makes it more difficult to process direct refunds in iPayment.
Any refunds that you try processing, which are not linked to a previous transaction will now require your account to have ECC support enabled + this can only be done by contacting Authorize.Net directly and presenting the case for why you need this capability.
iPayment will still show you the option to perform these refunds, but if you do not have ECC support enabled, you will receive the following error:
Error during refund: iPayment.Shared.Model.RefundException: Code: 3, message: A valid referenced transaction ID is required.
at IPayment.Control.Payment.CreditNoteRefundController.CheckForErrorsAndThrowExceptionIfAny(List`1 settlementResult) in C:\TFS\B1 iPayment\Main\Source\Code\Modules\Modifications\Control\Payment\CreditNoteRefundController.cs:line 148
at IPayment.Control.Payment.CreditNoteRefundController.RefundCreditNote(CreditNoteRefundRequest request) in C:\TFS\B1 iPayment\Main\Source\Code\Modules\Modifications\Control\Payment\CreditNoteRefundController.cs:line 51
at IPayment.View.RefundForm.ClickSave(B1ItemEvent pVal) in C:\TFS\B1 iPayment\Main\Source\Code\Modules\Modifications\View\RefundForm.cs:line 290
Which types of refunds are affected?
If you manually create a credit note and process a refund for it, that will always be a direct refund, and thus affected by the ECC issue.
A credit note you're refunding won't have a previous transaction reference, so we can't perform a regular refund in those cases.
If you want to refund a document which has been settled by iPayment, the correct way to do so would be to right-click the settled document and selecting the refund option.
This will refund the entire settlement and automatically create a credit note if the user chooses to do so.
Please note that the partial refund option also utilizes ECC refunds since it's otherwise impossible to refund a transaction partially.
For more information, see the article below