There was a small disagreement with the owner at the convenience store for 2,000 won

(1)There was a small disagreement with the owner at the convenience store for 2,000 won 51 v
(2)A convenience store has a beer discount on the day of the Asian Cup national soccer game 12000 -> 9800
(3)So I bought a beer for 12,000 won yesterday and bought the receipt, and I was going to pay again today to get the event applied. It hasn’t been 7 days since I bought it
(4)But the boss who works today said it wasn’t polite, so I didn’t want to raise my voice for 2,000 won, and I understood the boss’s position, so I just came out without much thought
(5)Would it be a very bad issue for the boss
(6)You might think it’s unusual, but in the first place, I bought the receipt yesterday and stopped by a convenience store on my way back from recycling, so please let me know if there are any convenience store owners