Lost old phone number authentication problem and backup codes

It’s been years since I’ve came back to use Razer Gold to purchase my currecy when i was trying to redeem my razer gold to some specific game currencies, proceeding the transaction needs an authentication code sent to my old phone number which is i dont have anymore and the back up code, which is i dont remember if i even made one before.

Please help maybe to change my previous phone number, I have all the details needed to proccess everything , It’s been days ive contacted support and messaged some support and they haven’t reply to anything i hope this one works thank you.