Registered itunes card... doesn't show up...

[Canerican]

Hi, I registered a $15 iTunes card on my Mac under my sister's iTunes account.
When she tried to access her account on her PC, the balance didn't add the $15... What is up

 

[Turkish]

Did you enter the code under the bar code or scratch off the top part and enter that code?

 

[Canerican]

The scratch off part of course.

I should be clearer.

The balance was $0.81 before the new card. Then it displayed $15.81 on my computer's in iTunes. My sister logged onto her iTunes about an hour later and her balance was still $0.81.