i cant find the email from a gift card i was sent online. How can i get the code resent

I don't see a resend button do you?

Has it been redeemed ? If not try contacting iTunes Support : http://reportaproblem.apple.com or https://www.apple.com/emea/support/itunes/contact.html

How/where was it sent to you ? e.g. if another iTunes user sent it to you from their account you could ask him/her to resend it : Resend iTunes Gifts - Apple Support

If you requested it yourself from iTunes does it show for you to contact iTunes Support about it : http://reportaproblem.apple.com ? Or try : https://www.apple.com/emea/support/itunes/contact.html