Savings Bonds Redemption

My deceased father left me Savings Bonds with me listed as POD. I attempted to cash a few of the matured bonds at my bank with a copy of his death certificate. Fifth Third Bank told me they do not cash bonds that require supporting documentation. I contacted 2 other banks who told me the same thing. In the past, I had cashed bonds at MB Financial (since absorbed by Fifth Third). The Treasury Direct website says that 95% of bonds can be cashed at your local bank, and that POD bonds can be cashed with a death certificate. Any suggestions on where I can cash these bonds? Thank you.