Sirius Radio won't stop calling me!!!?

They keep calling me up to ask if I want to extend me service and won't stop. I've called back and asked them several times to stop calling and was even added onto their "Do Not Call List". Today I got another call while I was sleeping (I work night shift) so I called them back to ask for a supervisor - they wouldn't let me speak to one. I'm getting tired of the calls. What do I do? Do I call a lawyer?