visa gift card decline

For a card to have a chance of being accepted it needs to be registered to the same name and address (including format and spacing etc) that you have on your iTunes account, and have been issued by a bank in the country where you are (and therefore the country which is on your iTunes account) - prepaid cards are likely to fail that. Do you have a proper credit or debit card (a debit card might not work) ?

In that case you won't be able to buy items from iTunes (I don't think that iTunes gift cards are available in the UAE ; I'm assuming that you are in the same country as your friend), you will only be able to download free items.

It's a prepaid card, they will fail the iTunes validation. Do you have a proper credit card ?