You'll have to contact the bank. I just placed a few orders via my Meezan Bank VISA debit card, without any problems. They charged a 5% transaction fee and payment was accepted within minutes of placing orders.
BTW, Standard Chartered Bank usually has great service so I'm surprised their debit/credit cards aren't working internationally.
As for solutions, you can create a wallet on WebMoney and pay through it. But since I've no experience with WebMoney, I'd advise you to proceed at your own risk.
MCB is by far the worst private commercial bank! Horrible customer service. Staff acts like government employees. I used to have an account there so trust me; I know what I'm talking about! As for their debit cards, they used to work globally, but not anymore. No one knows why because the staff wouldn't answer this question, no matter what!
I think it's top secret!
In any case, if you want good banking service then go to the underdogs i.e new banks which are trying to establish themselves! HBL, MCB, UBL, National Bank etc. are now hopeless.
True story!