Hello, @Merlins!
Please understand that we only provide community support through this platform, and we unfortunately may not be able to help you any further with lost or stolen accounts through here.
As you have already received a response from the in-game customer service and through the official support subreddit, we unfortunately cannot help you any further.
Should you require further assistance with this, please feel free to reach out the in-game customer service again.
Please know that an unsuccessful account recovery claim can result from providing insufficient details about your account, or trying to submit the account recovery request from an unfamiliar device. We recommend that you provide all the accurate and required details, and make sure to submit the request from a device that you use more often to log into your PUBG MOBILE account.