i have a hard time accepting that "agile doesn't work." "agile" is a bullshit word in and of itself. the failure is yours, whatever path you followed to it. my question then is: what did you do to prevent failure or improve upon your ability to deliver?
secondarily, did your old process "work"? my guess is no, given your attempt to use another process or methodology. but i would congratulate you on recognizing that failure and experimenting with positive change.