Clark, sorry to see that this is happening to you.
As someone pointed out, you upheld your end so that means this person is still obligated to uphold their end. If neighbor kids really did kill the snakes, it is up to "Runde" to seek compensation from those individuals (and should have filed a police report).
Unfortunately, the things that "Runde" has said/done, has the ring of untruths/misleading.
The photos he sent look staged to me. The "blood" (don't know what he used as blood), on the snake bag, is too red, too concentrated on just one spot of the bag, and too even. That is not what it would look like if a snake had been beaten, while in a bag, creating that amount of blood.
The snake looks staged as well. It is not limp, does not have the injuries consistent with that much blood, etc. Plus, there should be no reason for all those "blood" spots above, and around, the snake. Whether this happened, or not, those spots of "blood" would be consistent with trying to apply something on a snake.
Also want to add that, with very little work, I can get some of my Balls (maybe most) to remain in that upside down position.