You need not activate your ATM card to make payment for purchase online. Corporation bank enabled the online transaction for their customers using ATM card. So if you want to make payment, you simple need to give your card number and CCV in the appropriate places given by eBay and after you will be directed to your bank website to authenticate the payment. That is secured gateway payment and you need not to worry about the transaction whic will be made very safe. Hope you will understand better.