Why wouldn't GermanDumbEnglishBoy not try and retrieve his account from the hijacker?

And how would GermanDumbEnglishBoy know that Amir did/didn't hijack his account?
If the hijacker got in touch with GDEB, wouldnt the hijacker have to reveal some information proving that he hijacked GDEB's account. And wouldn't he use that as evidence to try and retrieve his account from the hijacker?
And on top of that, if GDEB was hijacked, why hasn't the hijacker used the account for some posting other than this?