Payment Didn't go through for Halo War 2 Complete Edition While on Sale and Now Back to...

I was wondering if there was anything I could do to get the sale price for Halo Wars 2 Complete Edition. I thought I had made the purchase a few days ago when it was on sale, and yesterday when I got back on again I didn't have it. It says that I haven't
purchased it. Now the game is back to full price.

:)