Do they have a website where you can log in or something? If not, I can't really thing of other ways of brute-forcing/cracking accounts for such thing.
You need to hack the Twitter or the facebook who is linked with the Pubg account, and by chance if he didnt link another social media congratulation the account is yours
You need to hack the Twitter or the facebook who is linked with the Pubg account, and by chance if he didnt link another social media congratulation the account is yours