Q: i got my son a gift card and emailed it to wronge address

We are fellow users here on these public forums, you're not talking to iTunes Support nor Apple - I've asked the hosts to remove your phone number and email address (it's not a good idea to psot personal info).

If you haven't sent to a valid address and it hasn't been redeemed then you should be able to try resending it : http://support.apple.com/kb/HT1541

If you can't resend it (and it hasn't been redeemed) then you can try contacting iTunes Support via this page : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page, then Purchases, Billing & Redemption

If you haven't already done so then try resending it to the correct email address or contact iTunes Support as per my above post