Does Blizzard don’t accept credit / debit card to purchase balance ?
I used two different to purchase balance. It takes forever to pend. Then I received an E-mail saying Blizzard Entertainment - Digital Purchase Failed. I have $20 balance. I tried to purchased certain amount balance so I can purchase World Craft 3
Seems like you should report this to the costumer support and not in a Warcraft 3 forum for PTR feedback.
My suggestion first talk with your Bank.
For sure you have some limitations there, not to pay on internet or 3d secure setup, or I do not know all those modern ways they invent to pay !
But for me is working fine, paid with my visa debit card, local currency, not even euro.