I have been using Flipkart and several other online shops for past years. I never had a problem with any of the items I bought from Flipkart till recently, when I bought a Micromax Canvas HD phone for my daughter. The phone screen soon developed streaks and discoloring. I reported this to Flipkart and got a detailed(though generic, made to fit all) email giving me some steps to try. These steps included factory reset etc., which did not work.
I requested a replacement(all within a month) and got a prompt email within few hours, scheduling the replacement. I got the new phone within 4 days and the courier collected the defective phone.
The response was quick, definite and clear. I knew what I was going to get and when, as a replacement. I believe that the real test of a service is when something goes wrong and you need it rectified. Several websites fail on this front. However, Flipkart rocks.