What is the best methods to protect altcoin from hacker?
take care of your private key, passwords and dont click any suspicious link that has been sent to you through pm, shared on any social media sites, etc. the only reason why hackers have the access on your account is because they successfully get your key.
secure your account especially your password, and don't enter carelessly, usually they use link links to cheat
also pay attention when you log in, it's as usual or there is suspicion