I too had a defective Audio CD from Amazon that I had ordered for my wife.
On Xmas day I went to the order online and completed the return process. It took 2 minutes. I printed the return barcode and address label.
I had it packaged up and in the postbox within 15 minutes.
I then received an email saying the replacement would be dispatched asap.
Yesterday it was dispatched.
Simple and an example to all online companies.