I'm assuming if you have an affiliate code you signed up with Amazon Associates and entered the code in the Amazon section of the Hubpages affiliate page under "my account."
To track your earnings go to Amazon.com, scroll to the bottom and click on "Join Associates" link under the "Make Money with US" category. Enter your e-mail and password. Once logged in your earnings report will be at the upper far right of the page. Click on "View Full Report" to view different reports like orders and earnings.
If you tried all of this already, you should contact Amazon about the problem.