@OP: It's mostly your own fault. There are several ways they can get hold of your info, and it's very unlikely it's due to a breech in SE security.

Obvious passwords, repeated usernames/passwords in several games/sites. The list goes on. Never use personal things in your password, unless it's so personal that only you know about it and you are 100% sure you havent mentioned it on a social media.

There are also things you can do to highten security, like using exclusive e-mail adresses for each game. Have a computer designated for only gaming and another for surfing, minimilizing the risk to click bad links, checking bad mails or ending up on hijacked sites on your gaming PC. Expensive sure, but so is the game you pay a sub to play if you think about what you spend over 10 years. Protect your investments.