Did you ever consider that you may not have fit their criteria or the fact that they probably have hundreds of people applying for one role. Also, I would assume you got an auto response initially that said if you have not heard within a certain time frame to consider yourself unsuccessful.

I appreciate that it is frustrating not to get a response but well known companies here will receive thousands of CV's a week and cannot hope to reply to every single one, particularly when all they want to let you know is that you have been unsuccessful - which you would have gathered in the inital auto-response saying if you have not heard etc.....

harsh but the reality I am afraid