In order to avoid hacking attempt in the future, you just need to follow the security measure mentioned below.
Please always use strong passwords and to change the passwords periodically. In that way, we can avoid such situations.
In conclusion, do not pay BTC to the scammer and do not reply to the fraudulent email message. The only thing you need to do is change the password to your email address and other accounts you have for safe measure.
https://botcrawl.com/hacking-alert-you-account-was-hacked-email-scam-tries-to-blackmail-you/