The Man from the Diners' Club (1963)

Meek credit card company clerk Ernest Klenk is feeling the pressure of demanding coworkers, new computers, and an upcoming wedding. This stress leads to a big mistake -- the accidental approval of a credit card for mobster Foots Pulardos, who is planning to flee to Mexico with his girlfriend, Sugar Pye, to avoid criminal charges. When Klenk tries to fix his mix-up, he gets dangerously involved in Foots' scheme.