Ok, I've been told the item refund is not possible after a purchase from shop. I do not get why can not get a refund. This is making no sense at all. If I can get my money back and return my accidental purchased item to the shop, why would that be an issue? It's just like it's never happened, problem solved. And you are telling me I can not get a refund for this? I want a good explanation for the reason why I am not allowed to have a refund from someone's shop, if someone wants to lie about their purchases, you have your logs and such such, simple issue with terrible answer, it's like you people are just too lazy to even fix these problems.

Ask yourself this question:

If you purchased from a player-run shop, would they have to give you a refund if you misread what the sign said and bought something accidentally?

Even if you threw the item back to them and they picked it up, they would be under no obligation to refund you. You bought from the sign, you paid the price, and you got the item. That same idea applies here. Be careful what you're buying.