Customer service is a lost art. Because I bought the books seperately I can't take advantage of the buy 2 get 1 free

I bought the Squid Definitive Guide in pdf format, I was pulling me ebooks on to my thumb drive and I thought hey I wonder if they have the Bash Cookbook in pdf format Yes you do, but I can't take advantage of buy 2 get the third free. I already bought the Bash Cookbook paper back, now today I buy 2 pdf books, one pdf is the same title as the paperback, thats a little over 100.00 dollars. It's amazing that your customer service department can't have a human intervene and allow me to cop a free book. What ever happened to the Art of Customer Service? A savy sales person would be all over this to score major customer satisfaction points.