If you're dealing with a financial institution, odds are they're covered in these cases by anti-fraud laws or provisions in your contract/service-agreement anyway. I expect the cops would roll their eyes and tell you to go away unless you want to risk a false-report charge. They probably see a lot of people trying to file reports against institutions for often-bad reasons and don't have much patience for it. On top of that, they usually don't give a shit even when it's a genuine complaint—the only reason to even go to them is to get (heh, around here, purchase, even) a police report for insurance, if that applies.