Tory Burch Miller Sandals

I literally just bought them last Sunday. The first time I ever worn them was yesterday and that's when I noticed they fit too big. When I checked the size it said 7 and I wear a 6.5. I would've taken them off but I was already at work and I sit at a desk so I didn't move too much in them. The only reason they're dirty is because obviously they're open so dirt was going to get underneath. They're basically brand new, I still have all of the original packaging that came with them!