The refund system is another gesture showing how much the company cares for it's customers. KUDOS!
I was super amazed when I read that you can give back skins and champions (3 per lifetime per account). Here is exactly what happened when I talked to Mr. Riot about this.
Mr.RIOT: Refund System now online, you can give back 3 champions or skins in a lifetime.
Blowfeld: Yeah, bye bye Xerath! He was the biggest mistake I ever bought. Thank you, Mr. Riot.
Mr. RIOT: Oh, only stuff you bought within the last 90 days...