This reminds me of some fellow I worked with over 20 years ago who agreed to do a contacting project, I am not sure the specs, but it was agreed that he and two people who worked for him would charge the client $100k on delivery of the final product. Similar take: they kept moving the goalposts of defining "final product," until he said, "no more changes until you pay for the ones we did." Client canceled the contract, but made the mistake of claiming they had never heard of him to the judge in court. So he brought a laptop, and showed the judge the finished product, which the client was actually using as their web front end.
"Oh, that's a test web site, not the real one. It doesn't count."
"So... he did do the work. You HAVE heard of him?" The judge found the client responsible for $100k plus court costs.
Client refused to pay. Claimed to have paid, the check was declined, declined check was cashed, they can't pay him because he was from a foreign country due to 9/11 (he was from the same Maryland county they were, not foreign at all), all sorts of changing stories. So he went back to court, got an sheriff involved, and sheriff came and seized a lot of the client's assets and auctioned them off. The client tried to pretend nobody was in the office, and fled out the back door like a secret door in a treehouse fort, so the sheriff was unimpeded in the seizure. Ther client went out of business, because part of the seizure was their SBO servers, and this was before cloud backups were a thing.