Specifically, what areas should the company concentrate on first? Why? How would you recommend that Amazon deal with these issues in the most cost effective manner?

Here is a list of the customer complaints broken down by category at Amazon.com over the last month.
Billing Errors 537
Shipping Errors 2,460
Electronic Charge Errors 650
Shipping Delays 5,372
Packing Errors 752
Construct a Pareto chart and discuss the conclusions you can draw from it. Specifically, what areas should the company concentrate on first? Why? How would you recommend that Amazon deal with these issues in the most cost effective manner?