I am posting my experience with purchasing tickets through Lessno.
Thanks to someone in an earlier post I checked them out because we are going to London next summer. They came up with an excellent price that was not offered on Kayak or Mobissimo. I did a search on google and read some good reports about them so went ahead and booked.
On their website once you have booked you can click on chat and you actually get an immediate response by a real person. Everything went well and I received the confirmation email that the tickets had been booked. I double checked on the "live chat" and the reservation was there. I didn't receive the ticket numbers by email when I thought I should (they say 48 hours) So I went back to live chat and she checked the reservation and said the tickets were issued this morning and she emailed me the ticket numbers immediately. So, all is well. I found they were so much easier to deal with than the airlines themselves. So, I do recommend them as it went so smoothly and we are definitely on the flight.

Did you check the actual airline website to see if the reservation is there?

I called Northwest and they have it so all is well.

Excellent, thanks! Keep us posted! It will be nice to add another 'reliable' tool to my airline reservation site toolbox

I did a search before I used them and they received high marks on the review site I found. I was very impressed with the way they handled everything. When I went to the Northwest site the reservations were there and I was able to add frequent flyer numbers etc. Apparently they are very big in Europe.