If you call the number back, you get a recording that thanks for you the call back. It then offers you the option of being removed from their 'Special Offer Promotions'. You simply press the key that they tell you to press for opting out. Hopefully that stops any future calls.
Keep getting call from 425-406-9220 (last call 7-10-13). No message left on the answering machine...
These are annoying calls... Simply don't know why they can't be stopped. NSA, are you listening!!!