The 20 000, if even legitimate, is separate from the 210.
Pay h4ns the 210, then sort out the problem.
In the real world, demands are subtracted from each other.

If you want to make it based on arbitrary claims, then sure. Perhaps h4ns suffered consequential damages due to the lack of the 210?
If you're going to go circular with the payments, why not just pay your plumber for your groceries? If you can graph it, you can connect it.