If you bought the account and the account was banned later without you doing anything. I think it is not ban evading on your side. Ban evasion is for the banned account owner that violated the forum rules.
Since you did not violated any forum rules and you are not banned you are not ban evading at all.
On your new bought account that was banned, I think you have the right to appeal it to the admins that you only bought the account. You have to prove that you are not the alt of the banned account seller, I think admins can easily verify that you are not an alt.
How exactly does the banning system work for spamming? Is there 3 strikes your out banned for good. Or is there a waiting period.
Typical sig spammer ban duration escalation is now 14 days, 60 days, permanent. If it's someone I truly feel just needs a warning it will be 7, 30, permanent. This needs to stop so I'm going to be much more aggressive. If 8t doesn't work there's only 2 options left, and neither are good.
I do not unban accounts because they were sold. Many accounts being sold are on their second or third offense.
OP and all his alts are banned.