I am unable to add Vanilla Visa Gift Debit Card to Apple Wallet

I got a Vanilla Gift Visa Debit card as a graduation gift and I’ve tried several times to add it to my Apple account/Apple wallet, but it says it’s not valid. I’ve been over the list of accepted banks in the U.S. for Apple and the bank that issued this card is on the list yet I still can’t add it to my account or wallet. I don’t get why Apple says the bank that issues it is valid but the card isn’t and I know that the card is activated because I checked with VanillaGift.com. I simply only wanted to use the funds of the card on in-app purchases on one of my games as I am without a job and currently no money on my actual debit card. You can’t cash the gift Visa or use it at an ATM, but I only want to use the funds on my Apple account. What should I do? Would I be able to purchase an Apple Gift card with the Vanilla Visa at a store that sells Apple Gift cards? Would I only be able to use the Vanilla Visa at an Apple Store to purchase a gift card? Or is that not possible and I should use the gift card on something else?

[Re-Titled by Moderator]