Stupidity In Full Bloom

I work for a gardening company that has multiple companies under it. I work in a chat for all the companies and usually just answer typical gardener questions.

Visitor: “Hi, I have a question about one of your items.”

Me: “Absolutely! How may I assist you today?”

Visitor: “I see here on this iris, it says it comes packaged as ten per package. So how many will I get in each package?”

I have to read the question a few times to be sure I understand. 

Me: “For every 1 (one) package of that iris, you will receive 10 (ten) of the irises.”

Visitor: “But how many exactly?”

Me: “You will receive exactly ten irises.”

Visitor: “I don’t think you understand. If I want one order, how many irises will I receive?”

Me: “If you order one order, you will get ten. If you order two orders, you will get twenty. Multiply each other by ten, and that’s the number of Irises you will receive.”

Visitor: “That doesn’t work if you multiply it by zero.”

Me: “I am very sorry for the confusion, but it does work; if you order zero orders you will receive zero irises.”

Visitor: “I didn’t come here to do math, I came to garden, and you are no help!”

They then disconnected the chat. I still don’t know what I could have said to help.