Hi Adel,
for info, Tiger of Korea is entirely a separate entity from Tiger of Japan, which the latter has been proven in the world of household products.
I happen to pass by Tiong Bahru again, and overheard another victim whom uses Tiger wok, similar experience as mine - not properly seasoned, or defective factory coating that results in the brown stains.
Before you guys buy any wok, drop by at Tiong Bahru market and visit this stall (market selling domestic consumables) facing the wet market.
Go have a good look at how well the wok is seasoned there. As with my previous posts, for S$50, it is worth a consideration (bearing in mind, you could also enjoy some nice food there).
Once again, I have no commissions (I come from a very different industry). Just wanted to forewarn people against probable or unanticipated shoddy sales tactics or products.