I need help with gift-card purchase and support?

I asked my dad to buy me a digital Itunes gift-card, but he bought me the wrong one...

He bought the digital applestore giftcard instead, he didn't know...I called support, and the lady said she

send the info of my case over to support or whatever, she gave me a case number, but I forgot to ask

how long this might take, I haven't even gotten an email notification yet or anything...I haven't bought anything

with the card yet, I just want the digital applestore card switched with a digital itunes card...