Little thing with the store... Buying RP

So i was purchasing Riot points in order to buy my friend Bloodmoon Yasuo. And ofcourse it has the Security number thing even if you have your number saved... As i clicked my cursor onto the Lines in order to put in the 3 didget number... it dissapeared. i hadnt put my numbers in yet, so i said "Screw it" and put Pay Now and it accepted it.

How am i going to be secure now knowing slipups like that happen once and awhile....