Refund
A refund was the act of paying back a customer for goods or services purchased that they were not satisfied with.
In 2365, during a negotiation with Slade Bender, Jean-Luc Picard (as "Dixon Hill") asked him, "And what are you here to do? Ask for a refund?". (TNG: "Manhunt")
A lack of refunds was standard Ferengi policy, the very first Rule of Acquisition stating that "Once you have their money, you never give it back." (DS9: "The Nagus")
In 2374, when Julian Bashir, Miles O'Brien and Alexander Rozhenko were on the path to Kal'Hyah in preparation for the marriage of Worf and Jadzia Dax, they ordered a large feast at Quark's Bar, Grill, Gaming House and Holosuite Arcade after it seemed that the wedding was off. However, Benjamin Sisko, also on the path and believing it to be back on, came and took away the food, stating that there was no food for those on the path. Quark then gleefully noted that there were no refunds either. (DS9: "You Are Cordially Invited")