U.S. retailers, facing ambiguous judicial rulings and federal regulations about automated calls, have told the U.S. Supreme Court they feel forced to choose between withholding communications that their customers want or exposing themselves to “rampant litigation.”

The Retail Litigation Center and the National Retail Federation filed a joint amicus brief Tuesday, asking the Supreme Court to end the ambiguity. The case involves the American Association of Political Consultants Inc.’s First Amendment suit against the Federal Communications Commission, seeking to strike down the FCC’s ban on automatic dialing or so-called robocalls.