Completed the game with all spam answered and upgrades got, very nice. I got 2 small nitpick though if you don't mind.
First, I think the phishing mail shouldn't be allowed to spawn right on top of the cursor. unless you plan to add an upgrade that makes that impossible, I think you should make an exception so that it won't spawn and insta-lock you right then and there. alternatively, make it so that you have a brief window of time to respond to the mail spawning on top of you, because no one likes getting spawn locked like that.
Second, it seem there's a bit of a visual error when you drag around in the upgrade menu, the upgrades is placed on top of the black outline & header thing which looks really strange. Thankfully it doesn't seem to cause any problem, but it still look weird.