There is something wrong in the height of your cover. Your TT is 11'6" which is normal and even though 11" higher than my Bullet, my ADCO cover comes down about 12" below the bottom of my TT walls all the way around and I have a good 4 ft of extra strapping on each one . At the very least since you are a little higher, your cover should come down fully to the bottom of the camper walls. Are you certain it was totally open and not still folded on the top when you put it over? Did you verify that by getting on your ladder and making sure it was smooth and totally deployed? If so, just call them Monday and tell them your issue and specs and I'm sure they will exchange it. They have been in business just making covers for 60 years! They will make it right I'm confident!