How can I verify credit of an itunes card that has already been redeemed? My Grandson and I both redeemed itune cards on our shared account about the same time. There isn't a credit balance after his purchase?

I purchased 150 dollars worth of credit but it states that the code has already been redeemed. how am i able to get my $150 worth of credit back? It wasn't even redeemed by me.

Have you checked the account's purchase history to see if anything could have used up the balance : See your purchase history in the iTunes Store - Apple Support ?

If there aren't any purchases then try logging out and back into the account (e.g. on your iPad tap on your id in Settings > Stores and then log back in) and see if a balance then shows on it. My account's balance shows at the top right of the store's page on my computer's iTunes, by clicking on my name towards the top right of the iTunes screen, and by logging in to view my account via the Store > View Account menu option. On my iPad devices it shows at the bottom of, for example, the Featured tab in the App Store app under my account id (or you can view your account via Settings > Stores and it should show on the screen that you are taken to)

This will not work, however, on a Family Sharing account. There is no way to see credits on the non-organizer's account from the organizer's account, even when the non-organizer is a child. This is maddening.

Purchased it where ? Have you contacted the person/store that you bought it from ? What did they say ?

I have iTunes gift card and it has been already rede

You've just bought the card ? If it's already been redeemed and you weren't the one that did so contact the store that you bought it from