If you want to contest misinformation you have to do it in writing, and I believe the forms are on their website. The Customer Service people at Chexsystems can't do much for you and are generally pretty rude (and I say this as a former employee...). Not that contesting the information really DOES much, but it's a good step to take. Pretty much, unless the bank will agree to remove the information you're stuck waiting for it to fall off your record in 5 years.
Their system really, really sucks.