But we sent the file!!!!
I used to work at a company that did batch data processing for many large financial institutions, and occasionally they would fail to send us the files. So it was part of our job to call their technical teams to chase the missing data.
On one occasion the user was quite insistent that they had sent the file to us and it must be our fault. Their evidence?
* an image scan
* ... of a photocopy
* ...... of a fax
* ......... of a windows screen shot ( win95 possibly even earlier )
* ............ of an open file explorer window containing the file they had saved to their desktop
A+ for effort, but nope that's not what "sent" means :-)