Heli-dum, Part 3

I work at a popular party supply store. I’m up front cashiering, answering phones, greeting customers, etc. I get a call and this conversation with a very angry customer ensues.

Me: “Thanks for calling [Store]! This is [My Name]; how can I help you?”

Customer: “I bought a package of your latex balloons and they’re broken!“

Me: “Oh, that’s weird! How are they broken?”

Customer: “They won’t float when I blow them up! You changed them! I want a refund!”

Me: “Well, that’s weird. We haven’t changed our latex balloons in years. We can guarantee our balloons to last ten hours. When were they blown up?”

Customer: “I blew them up! Just now! They don’t float! Give me back my money!”

Me: “Sir… how did you blow them up?”

Customer: “What do you mean?! I just blew in them with my mouth. They used to float and now they don’t.”

Me: “Sir. I can assure you, they did not float when you blew them up, and they aren’t floating now because you need to fill balloons with helium for them to float. Helium is lighter than oxygen, so it won’t float if you just blow into them.”

Customer: “That is ridiculous! They always floated before. The balloons are broken.”

Me: “No, they aren’t. It’s high school chemistry.”

Customer: *Hangs up*

Related:
Heli-dum, Part 2
Heli-dum