I would wait until Monday before trying to contact the seller again. In the meantime, sort out how many you have from the list and how many you don't, and check pinpics.com to see if any that are not from the list are not tradable or are Sedesma.
Even so, the seller said in the auction that the pins sent would only be from that list, but they sent you pins that were not on the list. That alone should be cause for an "item not as described" dispute. They also said the pins all have the Disney backstamp. It sounds like that was false as well. Plus, you're missing 27 pins.
If you find even only one Sedesma pin or even only one pin that will not be tradable at the parks, file an item not as described dispute.