I guess that's my problem! I don't see what I did that was against KS policy's? If you have a different take then let me know because I honestly don't see what I did that was against them?
I sympathize with your situation, but there is no legal requirement for KS to let everyone have an account. It's a privilege, not a right, and all attempts you make to "prove" you are might be seen as argumentative/confrontational, especially if you continue to do so. I don't feel you did anything wrong other than being ignorant of their interpretation of rules. Your efforts to try to prove your point may just be a hassle they do not want to deal with, and one they don't have to deal with (legally).
They perceived the violation of a few of their Terms of Service rules.
"
Only one (1) account is allowed per business or individual. "
"
Posting advertisements under multiple business names with one (1) account is not allowed."
They use an IP check for this, regardless of how flawed you or others see it, as a method of identification. It's a simple solution that does come with flaws, but works for the majority of the site's users.
I don't think you violated the "don't let anyone who's banned obtain a new account" but it could be seen as borderline due to your shared business transaction and posting animals from his computer. I think you genuinely did not think about how it would be seen, especially if you didn't know he was banned. Still, it's probably too close for comfort for the (volunteer?) staff at KS to mess with.
Some scammers don't use their real names for scamming, they use fake names and use their real ones only when necessary, possibly to circumvent a ban on their "fake" account(s).
You also don't want to deal with the violation of being "Abusive/Belligerent/
Argumentative to Staff" by pushing this too aggressively.
You can also give them feedback on how you think they can improve upon the IP check system, but:
"However, please understand that when we make, change, or eliminate rules, we have to consider a variety of ways they impact the web site, and just because it appears to be a good thing, from our perspective your suggestion may in fact be unworkable."
Best of luck in getting re-instated, but I would totally stay away from using a lawyer for this matter. Since you don't sell reptiles for a living, you don't have to be on KS and have many other websites to sell the animals you recently purchased.