Originally Posted by
odom4president
And how exactly do I purchase a credit? I see the option to purchase points but not credits.
You don't purchase credits. You make a transaction combining your existing credits (worth 1200 points each) with the appropriate number of extra WN points to get to 19200.
It is not automatic; you have to authorize it specifically. It is right on top when you click the blue box with yellow lettering that reads: "Where are my Old Credits and Rewards?"