Same problem with me, I am using MasterCard debit and I get Transaction Denied when trying to submit my application. I know that my card is valid with enough funds and I have previously bought services(currency for War Thunder game XD). So I can only assume the problem is with them.
I did notice that in my last three payment atempts the billing page has gone haywire, like greatly zooming in when entering card data and CVV.
Update:
I tried using my moms mastercard(Canadian) and it worked. I dont know why my vas declined, didnt contact the bank tho. If you can just ask someone from Canada to give you the data and just make a payment