Walgreens didn't verify a gift card i purchased
Walgreens didn't verify the gift card.
See this Apple article: If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card
If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card - Apple Support
Beware of -> About Gift Card Scams -> About Gift Card Scams - Official Apple Support
Contact Walgreens and check with them, get your money back.
If you still need help, get support from Apple directly -> Get Support or call Apple in your region see -> Contact Apple for support and service or check -> here for more support and assistance.