Me: “This is [office]. How can I help you?”

Caller: “I was checking to see if you have received my fax.”

Me: “I am sorry, that has not been received.”

(I verify the fax number.)

Caller: “Well, I wrote on the cover letter to call me if you didn’t receive it. Why didn’t you call me?”

Related:
Taxing Faxing, Part 2
Taxing Faxing