Why didn't buy gems in game clash of clans with using iTunes gift cards

Without any information it's difficult to try and provide help. What happens when you try to buy something, if you are getting an error message then what does it say ?

If you are getting a message to contact iTunes Support then have you done so ? If not you will need to do so (you already know that you are only talking to fellow users on here) :

- go to http://www.apple.com/support/itunes/ww

- click on your country's flag (the country where you are, and which is therefore the country on your account)

- click on Contact Support towards the top right

- click on Get Help under 'Talk To Us'

Or use this form : https://www.apple.com/emea/support/itunes/contact.html

If it's a different problem ... ?

This is a volunteer forum, and as volunteers we can not remedy disputes to purchases made in the App Store. You need to contact Apple. You can review your App Store purchases here.

See your purchase history in the iTunes Store on a Mac or PC - Apple Support