Retailers hope the billions of dollars consumers spend each year using their debit cards will convince the U.S. Supreme Court to keep their fight alive against the Federal Reserve.

The National Association of Retailers and other groups asked the Supreme Court to extend the deadline for appealing a lower court ruling until July 21. The current appeal deadline is June 19.

"By ignoring the plain command of the statute, the (Fed) has allowed (card) networks and banks to continue to reap unreasonable and excessive fees from merchants and consumers," the group wrote in its application for appeal. "The District Court understood the implications of the (Fed's) statutory misinterpretation, but the Court of Appeals disregarded the plain letter of the statue."