i wouldnt buy an account at all, because there are no ways to change the e-mail address assigned to the account your buying therefore, the person who sold you the account can reclaim that account whenever they want, they also get the billing e-mailed to there e-mail also if u buy something on that account. so they can use that as proof to change the pass again along with there payment info they have used.
just wouldnt trust anyone bar good gun players.
hope this helps some people,
as my account got hacked but i aint too fussed because i never played ko anyways, just trying to help people from doing the same as me