The cost of litigating a contract would have far exceeded any value I could have possibly gotten from the project. The distraction and reputational damage from the ensuing fight would have been even worse. The best policy was to be be polite, and make the payment promised and move on. No need to belittle or argue with the candidate. I chalk it up to a learning cost in the business. I now know one way of hiring that won't work for me.

The irony is that the project had no value to me. I had already implemented that feature, and just wanted to understand if the candidate would be able to do the work I'd already done for myself. Indeed I picked the problem because I had solved it myself under timed conditions and knew how long it would take me. I wrote the code for the feature in about 20 mins and then tested and checked-in under an hour. I expected that a new person with less experience and skill than me would take about 3-5x the time, and that would still be okay. Even if they took a day that was not an issue for me. Which is why I paid them for one day of their time. They might have taken a whole day. But 30 days was somewhat too long. Thankfully I'd priced it at a fixed cost. So my downside was fixed.

Still the learning was not cheap. I was paying what would be considered consulting rates in India.