A correct card registration process should go as follows:    You enter your card details. You’re redirected to your bank website (card issuer) to go through the 3DS process. This process usually requires mobile authentication, meaning confirming the transaction in your bank mobile app or entering SMS code sent by your bank. In this process the card is temporarily charged 1 PLN which is automatically re-charged back to your bank account just after the process is finished. Your card is added, and the registration is successfully finished.   If, after many trials, you still encounter problems adding your card, please contact us via kontakt@spark.pl. We will be happy to help.