Gak, it is just that kind of reply from a seller, that ebay protection was set up for. Did that seller think that sending the poster in a flimsy tube, with a couple foam peanuts, used as end caps, taped to either end, was also acceptable? Mama mia!!
As Tob mentioned, you wont have any problem getting a full refund here. And I'm sure ebay and paypal woud also "enjoy" seeing the poor packaging, as well, if need be.