I have a past due bill from a transaction that i didn't authorize, now i cant afford it and...

Hey Anthony

Thank you for taking the time to post this on the Xbox Forums. We understand that you are inquiring about a past due balance on your account.

Under normal circumstances, you would have to pay the
past-due balance to unlock your subscription.

However, in this instance, I would have to recommend that you
contact Xbox customer support as they would be much better equipped to assist you with arriving at a favorable resolution.

I hope this helps.

Remove credit card and contact XBOX support.

You can also activate double security measures for purchases.

Tell me more about what hapend

you might have too go into your billings section on your xbox / settings the billing and accounts and remove your credit card / or debit card or what ever you have your money coming out of also for extra security you might want to try putting in a passcode
so that way who is taking money out of your account . will need that pass code . the number to call xbox is 1-800-469-9269. And ask to have a refund. if there are any other questions feel free too . let us know thank you and happy gaming.

Here is their contact page.