How can you reset security questions on an Apple ID when you have the password, but the security email is incorrect?
Focus on iTunes billing support. When you need support on a device and the software support window is over, you pay for that help.

iTunes billing support is generally free since you can't spend more money in the store without a working account. You always have to get a support person to call you since people that have access to the store accounts are a very limited subset of all the support personnel.

Just be persistent - keep good notes, provide a phone number where they can reach you and have all the details of the account you can muster ready. Things like purchase history, credit card bills so you can tell the person the last two or three purchases made from that account in terms of date, transaction number and amount.

Once you've gotten the password reset, you can go back and fix all the security questions at https://appleid.apple.com

Worst case, you can add a new email address to the account, verify it, and then see if you can send a security question reset after that email is verified by Apple and in use for a week or so. Also - make more purchases from that account (free apps are fine) to show that the device that was registered to that account is still in use and still associated with the account even though the email address on file is new.