My account got hacked, and they are selling it in a marketplace

my account got hacked and the hacker changed the email to something weird with this domain:

gppprobus.com

I tried recovering my account using the official epic recovery page, but I got this response:

I did submit an appeal request and I’m waiting for a response but I don’t think they would recover my account. what should I do? I have all the receipt of the assets I got from fab and when I open the login page of epic on my browser it still has the cookies and knows my account’s username, but it shows a different (hacked) email for it, see it says “welcome back”. I hid the full email and username but I can set it to the support if they’re here.

I googled the domain that was used for my account after it got hacked to find out more about it and saw this:

apparently the hacker is selling my account among tens/hundreds of others on this website:

x-market.gg

my question is: how can I prove to the support that I’m the owner of this account now that it’s email is changed? on the form there wasn’t a place to upload all my receipts and other information, there was just a basic text form which I used to explain as best as I can. I don’t know what else to do.