Same problem as I had a few weeks back. I was just trying to buy another game (I bought something else with no problems a few days ago) and again got this error message:
"Sorry, we can't accept your purchase at this time due to the updated 2015 VAT regulations. Your billing address does not match your purchase location (HU)."
I'm definitely not in Hungary (still), and I have emailed support twice with no response. Can you please look into this for me?