I have done exactly this! Given them fake credit number and other info, and kept them online for about 10 minutes. When I finally revealed what I'd done, I suggested they quit calling or I'd keep wasting their time if they did. I did this about 2 months ago. I've only gotten 2 calls since then. Before that I was getting 4-5 a week.
Called 10-19-2011 @ 15:42, answered call and pressed 1 to speak to a representative. Asked her to remove number from their database and she promptly hung up. Wasted a little of her time too.
I thought I was on the 'Do Not Call' list but apparently not - I received my first call from this number today but I have also received calls from other numbers such as this offering to lower my interest rate!!
So apparently 'Do Not Call' doesn't work. GRRR - I'm tired of these phone calls