A Berlin couple who learned they were paying toll bills intended for a state lawmaker recouped more than $500 from EZ-Pass, but they say the experience exposed flaws in the massive toll paying system.

If E-ZPass was to be believed, Dick Benson’s white Chevy Tahoe and Gail Benson’s black Volvo S80 had secret lives. The Volvo went on puzzling trips every month, according to the electronic highway ...