Buy XBOX 360 game without XBOX 360?

The title sounds stupid, but things are tricky.

I got 25 euro credit with the intension that I would buy it on my XBOX One GTA IV.

You can only pay for backwards compatible games with a credit card.

Now I need either an XBOX 360 to buy it there in the store, or an emulator.

Is there a 360 emulator that lets me handle the store? Is there another option?

You can add a Paypal account on the Microsoft website and pay for the game in the Xbox store.

I would still like to pay with my credit anyway.

As you have already noticed, this is not possible.

Isn't there an emulator or whatever?

Nothing I know.