If you accidentally downloaded a Vita game instead of the PS3 version, then the simple answer is no.
I don't think Sony could even remove the Vita item and replace with a PS3 version on your download list - even if they wanted to help you.
No. You can transfer the Vita game to your Vita (although it's faster just to download it from the Vita store), but Vita games can't play on the PS3. However, you can still remote play PS4 games on the Vita. And Japan has a PS Vita TV that will allow for playing Vita games on your TV. But there's no North American release date for that yet.