I worked on a system prototype for a

I worked on a system prototype for a local non-profit.
A month after sending a .zip file attached to an email, they told me they never
even received the files.

Me: Hello [client], I’m sorry that you did
not receive the files you needed. I’ve attached them to this email.

Client: We do not have ZIP Drive in our
computers. Can you run them over to us in a flash drive?