just noticed I have one game less in my collection on here than yesterday, apparently it's shantae:half genie hero. whats up with that?! :(

I still have my copy. Have you contacted support?

Did you buy it here or through a key-reseller?

very weird, it's missing from my orders history as well. I bought it the day it was released on here, contacted support.

If it's actually missing from your orders in your account, that would be very strange.
Did you check your confirmation email for that purchase?

I assume, you keep your emails (exactly for this reason).