A credit card is typically unsecured debt and they shouldn't be able to touch your refund.

Unless the credit card is provided by your bank and they are simply retrieving funds that are deposited into an account which they control. In either case I'd take Todd's advice and switch banks.
Several years ago I owed the IRS a relatively small amount from a "mistake" that I'd made several years earlier.

Just for fun I researched different options and forms that I could fill out and it turned out that I could have taken about 5 years to pay off a small amount with almost no penalty. Do some thorough research on credit cards and you may find a legitimate similar option.
FWIW I finally got tired of playing around with the IRS and just paid it off in full.
