How to report an issue with your iTunes Store, App Store, Mac App Store, or iBookstore purchase

I followed the instruction on http://support.apple.com/kb/HT1933 to report an issue with my app purchase from apple's app store. After "4. Click Report a Problem next to the item you are having an issue with.", instead of the described "5. From the Choose Problem dropdown menu, choose the appropriate issue", I am always directed to "http://www.apple.com/ca/support/itunes/" in the web broswer. If I simply click on "resend" in itunes, then I am prompt with "Your request is temorarily unbale to be processed. Please try again later."

I've checked on several purchases' invoices, and all have the same issue. This happens on both macosx lion and windows 7 with the latest itunes. Does "report a problem" actually work? or there's some specially settings I need to do?