I bought the standard edition of Mafia 3, the Deluxe Edition was released the next day.
Buying the DLCs separatly would have cost me more.
It was refunded instantly (I explained the situation when asking for the refund), even if I already downloaded the game, no problems.

A simlar situation happened with a different game (which I currently don't remember) during a sale.

I've asked a refund a couple of times when I accidentally bought the wrong edition of the game, probably the base edition instead of the complete edition including all the DLCs.

As the OP of this thread, I feel the need to say that I just re-bought Syberia 3. It shall have another chance.
It is a series of great historical importance in gaming (not only in adventures) and it would be a thing for me not to possess a part of this series.

Kane & Lynch 2 : Dog Days

I asked for a refund after I realized that I bought the censored german version.

I once refunded Stories Untold. The requirement only said "graphics card" or something and the game ran in slow-mo on my old laptop with Intel HD 4000 graphics. I have since rebought the game on a sale and it runs great on my new laptop.

Only did it once or twice, instantly, after a buying mistake (due to a confusion about editions - like, already having the game on gog despite what the page claimed, or misclicking a standard edition instead of a complete one).