AmeriMark / It takes to get 7 day shipping offer

Ordered a product 12/18/2006. Their site advertises a 7-10 business day shipping guarantee. When I called today [protected]), they are telling me that they have until 01/09/07 because their contract with the post office is for 15 business days, not the 7-10 days that they advertise. I still have not received my product. They think it is acceptable to take a month to get it after a 7 day shipping offer.