My purchase could not be completed

Hello ~You need to go ahead and contact iTunes for assistance from your iPhone message or:

iTunes - Official Apple Support

~Katana-San~

Then you need to do what your phone suggested and contact iTunes support at the URL provided in the message on your screen.

That is not here. This is a user to user forum and Apple isn't here. Just other users.

As I suggested above, the message on your screen tells you to go to www.apple.com/support/itunes/ww. and ask iTunes support. We are NOT iTunes support and we cannot help you.