OK. Tad made a mistake. He understands that, and so do I. Now I'll ask the same thing I ask a customer when I make a mistake, which I do every so often by the way. I ask "what would you like me to do to resolve this"? The mistake has been made, now what? If the buyer has something in mind, perhaps Tad will take care of the request. If there is no solution, if it's too late, then it's time to move on. At this point everything seems status quo. Tad's got his snakes, and the buyer has her money. Once again Tad is a good guy. He is not a crook or a con, nor do his animals suck. This was a mistake. Perhaps poor judgement. We all make them and all have them.
Having sold the snakes, for less than he intended, was a mistake.
Requesting extra money or the return of the snakes (if extra money is not sent),
after completion of sale and
after the buyer/agent had possession of the snakes (for a day +/-), was not a mistake. It was a deliberate, and conscious, action. A deliberate action that was wrong.
True, the seller refunded the buyer and it may not be the worse thing, that somebody has ever done, but wrong is wrong. No manner, of measurement, will make a wrong be anything but that.
It probably is too late, to make things right with the OP (or to have any resolve in this particular situation), but only because the seller, apparently, was/is not willing to do so.
However, whether this thread continues to have people posting, or not, at least the OP was able to share her experience and any readers can take from it whatever they will.
I just hope that the seller never makes this poor decision/action, should it ever arise again, in the future.