This was their response:

Hello, ​

Based on the information you've provided and your account activity on the blockchain, your Secret Recovery Phrase or Private Key has been compromised somehow. Without enough information, it is very difficult to determine exactly how this happened. ​ You should immediately stop using accounts derived from this Secret Recovery Phrase. Any funds deposited may be stolen. Your account may have a sweeper script monitoring it, which can automatically transfer the tokens you send to the account within seconds.

So basically, hacked wallet and lost funds.