I got pranked, I guess

I work in the SCO area, and there is this customer scanning his products with full attention. He was trying very hard to scan this flower p^t. But the scanner didn’t read the barcode after all of our tries. So I decided to enter it manually. When I tried to do that he said ‘Hold up, the scanner didn’t read it, so it has to be free right?’ I laughed because I thought it was a joke, and I didn’t mean to be rude to a customer. So I laughed and I continued to enter the numbers, and he said ‘You thought I was joking?’ and I said sir, I’m sorry but that’s not our policy. That’s not how we work. He immediately started to scream his lungs out about how I was being unfair and an a^s to him. He said he had to see the Store Manager because he needed to talk to him about how I’m an unprofessional and terrible person etc. Anyways, after all that yelling, SM came and both SM and the customer started to laugh their a^s off. Apparently, he was the manager's brother. And he just wanted to pull a little prank on him by using me. I don’t know if that counts as pranking me, but there was a prank, and I was right in the middle of it, and I just wanted to share.