iPhone XR activation lock after account was hacked

Hello,

I bought used iPhone XR at 8/2021 from Amazon seller. It was clean IMEI, without any locks and I put own Apple count on it with no problems. Also I had iPad on the same account. Early 2023 my apple account was hacked and hacker changed password and Apple ID. I tried to restore access to my account but no luck because I don't known new Apple ID but my Apple ID do not exist anymore. As part of troubleshooting with Apple support I created new Apple account with my old Apple ID and I successfully re created my Apple ID but it is empty. Even if iPhone still asking password for my old Apple ID, password does not match because internally it linked to my old account with different apple id and password. I successfully reset my iPad because I bought it new but I suck with iPhone... Apple refused to remove activation lock because I bought used. I have Amazon and Amazon Seller receipts, I have provided pictures that iPhone asking my old Apple ID that I have recreated it and have full access to new account with the same Apple ID but still refused. iPhone still working, I know passcode, it had my phone number on it, Airtag assigned to my old account still located and can be found on my billing/shipping address but I can't reset it because of activation lock. It is super stupid that legal second hand owner can't reset own device. Do you have any ideas how to remove activation lock?

[Re-Titled by Moderator]