My assumption of why it failed isn't very important, it could be wrong, but the symptoms (cannot input a non-hungarian billing address, cannot signup) and final result (gave up) are the same.
Anyway I tried to contact them through twitter (no answer) after going here (the page linked as "contact us for support"):
* something literally translated as "Visit the overflow of the stack". Funnily enough, Bing's automatic translation translates "visit stackoverflow" better than this.
* go to an MSDN forum. Which I did.
There, among plenty of thread of people unable to signup, I found this thread[0] In which the MS support person states (I will translate for you)
"The reported error is sadly common during signup, and finding the cause is hard (sic).
I suggest you double check you input correct data, check that you card is valid and that azure is available in your country. You could contact your financial institution to get more help or phone us"
Notice that this is a terrible answer because at this point they already know my card is valid and have in fact already detracted 1€ from it (both for me and the thread creator), and if azure isn't available in my country (which it is) why did they let me get to this point of the signup?.
Then there are three more replies from people getting the same result, opening multiple support tickets and not getting any answer.
One month later there is another reply from support stating that debit cards cannot be used for signup, sorry we don't say that anywhere.
This was one year ago, they still don't say that anywhere.
Awesome, but I was already trying with my credit card, after I failed to sign up with 2 debit cards (all of which got succesfully charged for every attempt).
Honestly, would you have kept trying at this point, hoping that in one month they get back to you?
Have you ever tried Microsoft Support (even if you have a fully paid up gold partnership agreement)?
At best you'll get some low end support peon who doesn't know ass from elbow. At best you get denial.
Then there's Microsoft Connect, their public bug tracker (for products they feel like pretending to support), which basically is a route for them to close every ticket straight away as not reproducible despite being reproducible by hundreds of people.
It was until the day it was down last year. At which point it was hopeless for nearly a week. I was on the end of a down system deployed to Azure as the technical contact. Not fun.
