Lamarr and Anthiel received a patent in 1941, but the enormous significance of their invention was not realized until decades later. It was first implemented on naval ships during the Cuban Missile Crisis and subsequently emerged in numerous military applications.
Cash back credit card reward programs started out rather simply, offering a flat percentage rate (typically 1 percent of purchases) rebated back to the customer in the form of a check at the end of the year or a statement credit.
A debit card and credit card are different. With a credit card you are borrowing money that you will later pay back. With a debit card you are using money that is already in your bank account. So where is the rip off in this case? The OP clearly used a credit card to buy the item as that is how it was refunded.