No receipt

A lady was waiting for her script to be filled but she was in a hurry so took her script and left. 

On the way out, our security guard stops her as she had a plastic bag with 3 boxes of Panadol and Codral Cold & Flu in it. She said she bought it from another pharmacy but couldn't produce a proof of purchase. 

She: This is ridiculous! I'm in a hurry and now you won't let me leave because I bought something from another pharmacy!
Me: Yes sorry but you need to provide a proof of purchase. If you can't then I'll have to check the security cameras for you to find out if you walked in with those goods.
She: I'm in a hurry! I don't have time for this!
Me: You need to provide a proof of purchase.
She: I can! You just have to come with me to the other pharmacy and they will show you! Do you even sell this?!?!? Have you checked?!?!??
Me: Of course we sell this. We're a pharmacy. No I'm not gonna go to another pharmacy for you. I can either check the cameras for you, if not then we will have to call the police. 
She: Fine check it check it! This is ridiculous.

So I check the cameras, yes she did come in with the goods.

Me: Ok I saw the camera. That's fine, you may leave now.
She: Give those back to me! 
Me: Next time, as a tip for you, you must have a receipt if you are buying things from another pharmacy. Otherwise how are we suppose to know? 

She storms out and then curses the security guard that he'll get a divorce because of what he did to her. Omg, its his job to check bags! Otherwise what's the point. What did she expect us to do? Just listen to her story and then let her walk out. That's dumb!