SpongeTech Delivery Systems, a New York firm that makes soap-filled sponges, is the target of a lawsuit from the Mets' Citi Field that alleges the company stiffed the ballpark out of $300,000 owed for stadium-related advertising by sending them a bad check and then promising a wire transfer that never came. According to the lawsuit, SpongeTech agreed to pay Queens Ballpark Co., the Wilpon family controlled entity that runs Citi Field, $3.34 million in a three-year deal that included a sign on the club-level fa?ade in left field, a sign on the outfield fence in right field and a panel on the rotating sign behind home plate.