1) If you're using PayPal, E-checks are not accepted.
 2) In case of Eximbay, if your card issuing country is different from your shipping country the transaction may be blocked.

    You may also check your account status and review buyer information you have entered before making the payment.

When using a credit card, you need to check the followings or contact the card issuing bank for more details.

1) Certain credit cards allow only domestic payments
2) If exceeded monthly-limit, payments will not be made
3) With chargeback history, a transaction may be blocked
4) Card holder's information must match with the buyer’s information