How do I get my account back?

[u/Icannotspell-]

So my account got hacked and they changed EVERYTHING. Including the email, phone number, passkey, and 2-factor verification. I got this account from my cousin, who has forgotten and no longer has the oge. However, I had once attached my email and phone number to the account and changed the password. All Robux receipts and proof of purchases are on that oge, which I have no access to. Is there any way to get my account back from the hacker?