I don't trust and nor like the refund policies/processes and all kinds of fences they implement, and often even after I have bought a game I will keep using the pirated version because it is more convenient (offline play, no need to login and it's already installed... when games are 100-150GB sometimes it's a waste of time to reinstall using Steam). Do you have another kind of usage that leads to these false positive?
No, pretty much same usage. I buy games to support the devs after I've already pirated the game and determined it's good, then I go back to playing the pirated copy.
Steam is pretty reasonable. If you bought a game in the past 14 days and played fewer than 2 hours, you can get a refund for any reason. You need only go to your recent purchases, “report a problem”, and with a couple of clicks you’re done.
If works incredibly well and with no hassle, I have done it a number of times for games which ran like crap on my machine or plain weren’t fun.
I’ve heard GOG is even better with their returns, though I have never tried it. And they sell games which are DRM-free, so even better than a pirated version.
I have refunded a bunch of games, never had any problem with it. As long as you haven't played more than 2 hours they refund no questions asked.