I Found an Unknown Email Linked to My PUBG Account

I discovered an unknown email address connected to my PUBG account, which is not mine, yet the system tells me to log in with this email. When I try to access the account change section, that email doesn’t even appear. I have no idea how this email issue happened or how to fix it. This is worrying because it might mean my account security is compromised. I urgently need assistance to resolve this problem and secure my account. Please respond as soon as possible. I’m frustrated and anxious about losing control of my PUBG account.