You have two Winn Dixie stores on Tamiami Trail right down the road from one another. Is it possible the lady meant the one at Promenades Mall to the south? The Lottery rep is only going to pull the info for the region, and unless she gave you an exact address / store number, the difference between North Port and Port Charlotte might be pretty irrelevant to her. It'd be worth checking the other store.
Also, there are eight Winn Dixie stores in the general area (each one 3-7 miles apart). I'm not sure how the Lottery feels about such activity, but if a number of them are managed by the same local entity it's not implausible that one store might have traded the 100X book over to another. Books do also shuffle around, get misplaced, get stolen. Someone else could have come in, asked for it, had it activated, and bought the whole book between the time when you called and the time when you got there (with a different clerk present). There's a lot of possible fault beyond just the Lottery.
I'm sure if you email that same office they can send you a list for the whole region.