I recently booked a return trip to makemytrip. When I went to the airport, I was informed that the going ticket had not been booked. I looked at the printout closely. The printout said that your ticket has been booked. On looking further, there was an interesting point - for the id next to the onward journey, the word FAILED had appeared. for the return journey, the normal id was present. hence, though the ticket for onward had failed, I had still got a "Successful booking" printout, possibly because the return had been booked.
So anyone booking on makemytrip - please check if the word FAILED has appeared anywhere on the booking. This was the negative part. however, I was pleasantly surprised by the following:
I called makemytrip from the airport - they informed me that the website had failed and asked me to book another flight immediately. I booked it on the same day. and they reimbursed the expenses later as well. very good response and customer service. tho there was a problem, they did try their best to rectify it.