Unable to purchase or download anything

Do you get any error message?

Also check https://billing.microsoft.com to verify your account is in good standing and there doesn't say anything about an outstanding balance. In the case of the outstanding balance, it might be
best to speak with Phone Support if you are unable to resolve it yourself -
support.xbox.com/contact-us

Let us know how you get on.

Greetings, aX Genetiicz. Sorry to hear you're having a billing difficulty. Can you please do me a favor and create a new thread detailing out your situation? This will enable us to help you with your individual situation. Thanks in advance!

I can't actually believe this is the only response I got.

Hi there,

If you have the exact error code that would be tremendously helpful in offering solutions.

However, if it is the case that you are trying to do this from the web, could I suggest you instead try from an Xbox 360? The web store does not yet support the use of the currency in the Microsoft Account (since the switch away from Microsoft Points) whereas
this operation can be completed from the console.

Let us know if that works, or if you are already trying this from a console when the error code appears.

Again, giving us the error code itself would be enormously helpful in resolving this for you.

You'll want to contact support and speak to billing. Http://support.xbox.com/contact-us