Where oh where?

[Kronos]

The way I tackle this is searching my email inbox to find the order acknowledgement or whatever. My email address only going back about 12.5 years though and I CBA trying to dig out the backup I have of emails older than that, might even have been lost in a HDD failure.

I've still messed up occasionally though and bought a game I already own.

The game had disappeared, I have email notifications of games bought which I used as evidence to Steam that I did indeed own the game which they reinstated with no explanation of how or why this situation had occurred.