Email hacked, security settings changed. Pending for 30 days, unable to cancel.

My email account was hacked and the security settings were changed.  Now, another email account of the hacker (*** Email address is removed for privacy ***) has been established to change security settings in the future.  That change is pending until Sept 4.  I cannot cancel the change, because an old alternate email account (*** Email address is removed for privacy ***) used in the cancellation process was closed long ago.  So, I am sitting on a time bomb unless I can get this pending change to the “Recently Updated Security Info” screen changed.