Ill tell you first hand, that it don't mean shit what keys, or the old info was. You don't have the current info SE won't do shit for you.
Sad to say but those accounts are a lost cause now. Only thing really you can do is try and trash their rep where they ran to. If they are rmt there, well it won't really matter anyways.
They can do something. You've been paying for a service you use/used/still want to use, and someone steals it. That's a crime, and SE can thusly look up your old information and cross-referance it with the information you're giving in order give you your account back.
What you need, though, is street name, real-life name, credit card number and activation codes.
Reason they couldn't do it before is because you might share account with someone (which, btw, is against the user agreement you agreed to, which is why SE is hillarious), or that you could have given it to someone and want it back (which you can legally do since you technically "bought" it), or that you sold your acccount (which, btw, is against the TOS since RMT is illegal. Your account is legally SE's account, and thus selling it is illegal).
Additionally, if you can prove that they didn't change the payment info yet, or that your account were stolen, but you still got billed for it while you did not have access to it, you could also bring up legal actions against the person that stole the account, since that's practically using a person's credit card without their permit, which is also illegal sicne the person is basically using a stolen credit card. And in that case you can go around SE and go through your bank in order to get your account back. Although it would be wise if you contacted SE about it as well.
Either way, depending on the situation, you can get more then just your account back
