Purchasing overwatch with prepaid cards?

I tried getting the overwatch normal edition for 39.99$ but for some reason it tells me my card information is invalid, but I am sure that it isnt. I tried paypal but nothing changed.

The thing is if you buy overwatch with usd instead of euros (which is how I was supposed to buy it in Turkey) its significantly cheaper. So what I am guessing is you cant buy the game with the prepaid cards if you changed your region to something else. But for some reason the error message is wrong and is telling me my card info is wrong.

I wonder if anyone has had this issue and if you are willing to tell how you solved it im willing to listen.