i just bought a apple store gift card online and i have recieved the email which contains the pin and card number , i tried to redeem on my mac and iphone , but the code was invalid, can someone help me figure out the problem ASAP

How are you trying to redeem it ? If it's an Apple Store gift card then it can only be used in Apple bricks-and-mortar stores and the Apple online store - you can't use it to buy content from the iTunes store.

And if it was an iTunes card purchased anywhere but from the Apple Store or within iTunes, you will need to contact the "retailer" who sold you the "card" and talk to them. Some of the sites that purport to sell iTunes cards and send you the code electronically are out-and-out frauds.

Regards.