Collection agency woes...?

A few months ago my wife and i defaulted on a credit card, because the interest rate got so high i couldn't make the payments. Now i am being contacted by a collection agency called NRC. I recieve at least one call a day from them, and have attempted to settle the debt, but they can't seem to offer a settlement without having my bank account number, etc. So far i have refused to give it to them, but they pressure me every day. I have asked for an agreement in writing, but they refuse saying they have to have automatic payments. They have also hinted that they will garnish my wages. Is there anything i can do?