This reminds me of my first "paid" job. I was contracted with a friend to fix the decaying IT infrastructure of a mid-sized local business. We were 18, early 90s. The contract was through a friend of my friend and was a shady affair from the start: nothing in writing or signed.

We agreed upfront to get about 600$ each, which was woefully little for the ordeal we had to go through. The place was a mess of DOS PCs, AIX workstations and ancient early macs. The backups were a cardboard box of unlabeled 5 1/4 inch floppies. We even had to solder our own cables to get some ancient serial printers to work and get the new IP network talking to stuff that wasn't built for it at all.

The owner was paranoid about security so we passworded everything that could be and compiled a long list of passwords.

When everything was working we sat with him to get our money, and then he said he had understood that the deal was $600 shared between us. He didn't budge, so we got nothing and he didn't get the password list.