We accept Visa, MasterCard, and American Express credit cards.
If you have double checked the card numbers are correct and the funds are available, the most likely reason your card has been declined is that you have an international hold on your account. We are located in Canada and your bank thinks the purchase is a fraudulent charge - so it is being blocked for your protection.
If this is the case, you just need to call the number on the back of your card and ask them to lift the hold. They can lift it automatically and then you can place your order!
Another possibility is that you are trying to use a pre-paid gift card or debit card that doesn't allow international transactions.