I feel for you. Unfortunately I don't see a reasonable cause to deny. I don't think you can deny customer A because of the tenant unless it is your bank's process to ALWAYS check out the background of all tenants in a rental application. Plus you probably can't inform customer A about your past banking relationship with customer B. Unless you can find a bona fide reason to deny customer A of their own accord, you probably have to take your chances at re-involving your bank with customer B.
This is purely the way I see the situation from a distance, not knowing all of the details. I wish I could tell you to throw the dart at deny!!
Going to church doesn't make you a christian any more that standing in your garage makes you a car.