Yea I think heard this podcast. Basically your email password gets hacked and once they have access to your mail they reset you're uber password. Once they have access to your uber account they immediately change the email and phone number on the account.

Some Insider info, I used to be a contractor for them at corporate.

The reason support is useless is because your account has 3 identifiers the UUID (nobody knows this, it's like 16 characters), you're phone number, and email. So once those are changed support has no way to find your account and that's when you'll get the run around because support can't access any billing info and can't look you up that way.

I'd suggest looking through you're old email for a legit p/w reset or if you still have the messages from when you signed up. You might be able to find the UUID that way.

Edit: you should also tell your credit card company to block any charges from Uber until this gets cleared up.