I agree that the snakes colors and pattern are something unusual, but the belly does not read as a Yellowbellies belly. I don't think anyone here meant for you to take any of their comments personally. People are just calling it as they see it, and trying to help you out in not getting swindled, potentially that is. I would definitely say yes to the last snake you linked being a Yellowbelly. It is also a good example of a subtle belly, only light speckling, but it's clearly there. If he has that snake for sale, why not ask for a trade? If he truly believes the snake he sold you to be a Yellowbelly, he should have no issues trading. Again, no one here is attacking you in any way, we're all just trying to be helpful! Good luck in whatever you decide to do!
Cheers,
-Matt