I don't have access to my old phone number and backup verification code.

I want to change the phone number on my account. The old phone number is no longer active here, and I can't register the new number. Also, since the two-factor authentication code is sent to the old phone number, I can't use it to make payments or log into my account. Please help!
 

I don't have a backup verification code either.I changed my phone, but my old phone number is still on my account.