if you misuse the camera, I dont think it is a good idea to return it.
From my experience, it is very hard to take decent pic/video while snorkelling.. when you are at the surface, the wave makes it hard to hold the camera steady. when you are in the water, how long can you hold your breath?
Not worth to spend this much for a one time thing. I suggest you get something cheap.
And adjust the WB while taking UW pics.
BTW, I'm selling my pentax s40 with factory housing for $65. listed at craigslist already.