Bans can happen to the character or the entire account. Also, sometimes Jagex just removes the character, sometimes they will ban the entire account, if there was a recovery.
I think this is what happened, original owner, or someone who has interest, has tried to recover it. Even if they don't succeed, the Jagex account might be locked or banned afterwards since it will be reviewed by Jagex.
The purchased character is likely gone unless you happen to know enough recovery info and want to get into a recovery battle with the original owner.
Any other accounts you own that are on that Jagex account can be recovered if you know enough information or are original owner, although this can be tricky as well as Jagex has been known to not offer any support for these characters if they claim you broke their TOS and want them back. I have however, known of at least one case where they were successful in recovering a character.
It is generally considered harder to recover a character on a Jagex account and they are most likely to catch if the account was bought or sold since an actual person sees the recovery request. Also, once you get it back, it is stuck as a Jagex account.
Once legacy (non-jagex) accounts become mandated to convert to a Jagex acc, it is possible that they will do away with the recovery system, and then this might change.
