what site are you trying to put a credit card in and what exactly is happening ?
usually if there is an error when trying to pay for something it comes down to the address that you have put on your account on the website does not match the billing address for the credit card.
but if you can get me some more details about exactly what is happening i might be able to help you better. You might also make sure that it is not asking for you to compete some sort of captha thing where you have to type in the funny looking letters before it will let you proceed.
it looks like the credit card did not work here either. i tried to accept the phone call request and it failed
i will put one back to you and we can try again.
You can also call the number on the back of the credit card and ask them if they rejected payment for us or more importantly for ourtime and if so why. they would know best if the request made it to them why they rejected it.
you can try our time at this phone number. they do not have great reviews for customer service but if you can get through on it i am sure they will be happy to take your money