Well, at first they talk about newsletter, then something wrong happen, they not even try to tell us what "newsletter is" or try to remind what "Newsletter" is and how to make sure the player already subscribed or not.
If they want they can just told us to go to the NCP located at Eden 2nd floor to claim the reward, but until now even the problem already solved, there is no official notice on how to obtain the piggy costume.
I even believe even the staff their self confused on where/how they must tell every player on Ragnarok about the piggy costume, and how to obtain it.
This begin to sound like the staff try to test how smart is the community and how often players use the forum, FB, official site, and Email.
If you don't know what a newsletter is then you must not have subscribed to almost ANYTHING on the internet.
A guide was released to show players how to make sure they were receiving a newsletter.
It's not a test to see how smart, they simply wanted to try another form of advertising and used a free costume as the reward for doing so. The newsletter codes failed so they took the list of those subscribed (minus Steam users because they didn't get noticed) prior to the finish date of the promotion and gave everyone an opportunity to get the costume via code the redeemer.