How retrieving my AdSense password w/out access to my old phone number ?

Hi all,

I've recently remembered about an old personal AdSense account I was no longer using since over 8 years in whom I should still have some credit to recover according to a recent email received by Google inviting me to withdraw my balance.

My login credentials are working perfectly but Google add an additional verification step by sms.
Unfortunately, I no longer own the phone number associated to the account so is there a diff. way to complete the verification process maybe by providing my personal docs to proof my identity ? How doing that ?

Thanks in advance for helping.