The thing is if you changed after the hack than you are not affected by the hack and if you had this password used nowhere else then it is very unlikely the hackers "guessed" it. Did you use it somewhere else? Or did you have a security question that was easy to guess or was your email account hacked? We need to find out how the hacker or hackers got control over the accounts.(Not saying mine and yours were hacked by the same guys)
You can try reasearch the database hack way back in 2015 where bitcointalk user's sensitive account informations including passwords and their e-mails are cracked which the forum advised to change their passwords so I changed mine and replace it with a much secure one than the previous but those users who are confident with their strong passwords didn't and until now they still didn't. Those who have weak passwords (naturally) has been cracked then hacked and some sold it for some bitcoins at the Auction board but don't get me wrong since not all accounts that are sold are hacked but most are.
