I found a good website www.BCSAlliance.com. According to this site, jacking up the rate using a bait-and-switch tactic is common in the credit card industry. The only way to refuse the new rate is via a written letter mailed using certified mail. If you were to call and notify the bank that you refused the new rate, the bank will conveniently forget about the oral refusal. This is also said to be a common/usual practice for all kinds of disputes with a credit card company. The following is a sample letter to dispute a change in interest rate from this website:

"Dear Sir or Madam: I recently received notification from you that you are [state change: e.g., changing the way in which you calculate the interest rate on my credit card.] This letter serves as my written notice of my non-acceptance to this change in terms to my credit card agreement. I understand that I have the right to continue to use my credit card under the existing terms until the expiration date on my credit card at which time my account will be closed. I also understand that I may pay off any remaining balance under my current terms."