Can I beat Sans Undertale and still get a refund?

Is it possible to buy Undertale, play through the entire game and beat the hardest bosses, and still be able to refund the game on Steam?~~~Music - Undertale

Greeting Card

Undertale: I beat sans. | Greeting Card

Sans, Undertale Wiki

Regretful Dust (RT!Dust!Sans), Godverse Wiki

Sans - Undertale Metal Print for Sale by RaggdyMan

Sans, you're a lazy sack of [SPOILERS] : r/Undertale

What happens if you spare Sans in the final boss fight? - Quora

I cannot beat sans and it's starting to make me upset enough to

I red that someone have beaten Undertale on a smart fridge

Who would win? : r/Undertale

Don't Kill Anyone in Undertale - True Pacifist Ending Guide - The

Tanphrous, Godverse Wiki