Have a look at a recent Forbes magazine article discussing why learning to deal with difficult customers is a good long term decision.
Here's a September 2013 article from the Harvard Business Review that talks about taking a holistic look at how your customers interact with your organization. Because of the silo nature of many companies, individual departments tend to look at their respective customer interactions in isolation. As the article points out, this is almost always a big mistake because customers don't experience your company in that way...they may often have to navigate multiple departments, telephone numbers, web pages, etc. in order to complete their interaction.
A provocatively titled article in the February 2013 issue of Fast Company discussing the often mentioned, but poorly understood, "core competency."
An insightful look at the details behind customer satisfaction in the Spring 2014 issue of MIT's Sloan Management Review.
The Revenue Impact of Great Customer Experiences, a white paper published by Medallia, March 2015