I bought a 20,000 won gift certificate, but nothing is being applied.

I bought a 20,000 won Unnie's Pouch gift certificate a week ago.

I've tried applying a variety of products evenly, but none of them are working.

Is it easy for everyone to purchase products using gift certificates?

I tried adding about 10 different types worth 190,000 won to my cart, but none of the gift certificates are being applied.