She never sold 500K since Ylvis - The Fox is the biggest INTERNATIONAL SONG OF THE YEAR in Korea and it is about to sell over 500K, this week or next week.
359 K it's what big local artist like 2NE1, SNSD, BigBang pull in 1 week where they are #1, Ciara is no Amerie aka the only American to pull Local numbers (even if she had the help of Local Idols like 4Minute, Se7en & TaeYang). And she is not Beyonce who sold 2 Millions records this year (but it was her entire discography and also she's been covered all year long by singers like Ailee, Hyorin, 2NE1, Kahi, and Reality TV contestants).

And It can't have a major success in Urban Radio in South Korea, on the simple fact there is no radio format there like in Western Countries.