How can you sell me a empty box

So upset. I bought a Samsung Galaxy Fit 2 from the Hi-Online store in Canal Walk. The display cabinet was locked with a battery operated key. The battery of the key was dead so they couldn't open the cabinet. They went to go check to see if they had one in the stockroom. The consultant found one. The consultant didn't check to make sure if there item was in the box. On my way home, I noticed that the seal at the bottom was cut. The watch was not in the box. I couldnt go back as it was past 21H00 and the store closes at 21H00. I am going back first thing in the morning and hopefully the matter can get resolved.