Can't redeem gift certificate.

I was given a gift certificate through my email. When I click the redeem button I am taken to the Apple home page where it prompts me to download ITunes. I have I tunes. I do not need to down load. I went to my iTunes page tried to redeem from that side but it asks for a code. A code that does not exist on my email. When I called the hot line they gave me the link to here. I am frustrated. 😟