Forgotten Apple Password and email address deactivated

Hi

I’m hoping for some guidance. My mother has locked herself out of her iPhone /iPad iCloud as she forgot her password . This would normally be a simple process however the actual email address associated with her account was deactivated / changed so we have no way of getting the reset. We have went through the process and provided the relative identification information including credit card info ( still paying for the iCloud) and clicked we don’t have access to the email account but at the end it simply says the recovery has been initiated and the information will be sent to the email address . We don’t have access to the email account!

the big issue here is that there is 10 years of photos and memories on the cloud that she really needs to recover if possible and we are lost as to how to fix the issue.

many thanks in advance