I have never heard of a website that requested the 3 digit security code for the original credit card used to purchase the SIM as a vendor is not permited to store this number for comparison unless you are trying to use the stored account number nd they want to validate it with the bank along with the security code. Be certain that you are selecting that you are using a new credit card number on the website for yor current card and use the 3 digit security code on the back of the current card.