Negligence

I went to the store to purchase an iron, however I saw a special on the Platinum sandwich press and purchased it, got to the teller and after paying I realized I was charged the normal price, after waiting a long time I had to then go to customer service to get a refund which was another long wait. I got home after work and opened my new iron which turns out to be old and used, I don't understand how can a returned iron be put back on the shelf??? Disappointing