Locked out of account on Meta Horizon!!!

Hello everyone hopefully someone can help me get this resolved. I'm  on an alt account because I no longer have access to my primary account. Im still logged into my 3s headset but completely locked out of the meta horizon app because I got a new number and o longer have access to the old number on my account. I have access to the email but it still requires the old number or 2fa which I no longer have access to. I've had my headset just shy of 1 year so I already through away the box that I guess has a different serial number on it. When I try to verify by using the serial number of my headset it asks for, it says support isn't available for my device. Like.I said im still logged into my primary account on my headset but no way of updating the information. Please help. Thanks!