i just got that reply from them
Greetings Marina,
Thank you for contacting First-pay, My name is Danielle from Customer Support.
In regards to your email, please be advised that management has informed us that you would not be capable of using the card at any online gaming company. This is presently not authorized by us, so this would explain why you are receiving the error.
I hope the above information has been found helpful.
With kind regards;
Danielle Browne
Customer Support