EA wallet payment option on the swtor website

I got some money on my EA wallet and want to use it to buy some cartel coins. I recently found out that there was a payment method of using my EA wallet, so that's what encouraged me to purchase cartel coins using that method of payment. Once I clicked on it, it said that I needed a "card code." Do you know where I can find the "card code" to use when buying cartel coins?