Is it a good idea to get an unsecured loan to pay off a credit card that won't lower a high rate?
Why not just get another credit card and transfer the balance? Many of them will give you special perks like x months of no interest for doing so. Also, once you call to actually cancel the card you will see for sure whether they really have any power to negotiate rates. From their perspective 15% APR is more than 0%APR which is what they'd get if they lose your business.