The only fix I can think of is a dry box inside the tank. The walls extending above the water line.
Couple of problems with this however, one is the footprint in the tank, kinda defeats the whole purpose of the wetside/dryside design of the pump. A second is the position of the pump, if you don't like it, you will be stuck with it. Getting the pump into the box-- and aligned right will be a hassle, that is IF you can get it in the box (eurobrace etc.) And the most important one, is the ventilation of the dry side-- it is going to get hot.
The question of a dry box for vortechs, comes up once in awhile. All in all, I would chalk it up to a 'learning' experience, sell/return it. Absolutely no reason to take a loss on it, it is a brand new-- unused pump.
Now the true addict, would look at the pump, and say "Hummmmm, already got the pump-- this is a good reason to get another tank that it will work on."
Jim