Yes you are right. It s typical problem but solution is very simple.
Turn off your pop-up blocker before continuing with the payment via Credit/Debit Card. Here is very simple manual for Firefox, Mozilla and Internet explorer:
Explorer
Tools -> Popup Blcoker -> Turn Off PopUp Blocker
Firefox
Tools -> Options -> Content -> Block Popup windows - must be unchecked
Mozilla
Tools -> Popup Manager -> Allow popups from this site - You must be on the first page of payment gateway (https://3dsecure.csas.cz/transaction)
