If you wish to test, in sandbox mode, how a
failed payment or
returned payment works, here is an easy way to test it. It takes seconds to return.
Got to Payments > Create Payment > Add Payment > Send Payment
Simply add the text "!failed" (without the quotation marks) into the Memo field of a payment in sandbox. The payment will automatically fail. Keep in mind this command has to be the first characters of the memo.
Add the text "!returned" (without the quotation marks) into the Memo field of a payment in sandbox. The payment will automatically return. Keep in mind this command has to be the first characters of the memo.
Memo field is a recipient facing field. Most clients use the the memo field to reference an invoice number or something else to help the recipient distinguish the payment from others. Information in the memo field will appear in white label payment confirmation emails and CSV exports. Depending on the recipient's payout method (Bank Transfer, etc, except PayPal), the memo field will also display next to the payment in their account.
Some banks display memo, however, long memo messages can be cut-off by banks due to character limitations
You can also use Tags to categorize recipients.