I got referred by an employee. During the first phone call I was given a "homework" interview problem. I'd call it medium since it wasn't very complicated, but required some work. After I've sent my solution back to recruiter I waited a week to get any reply. Then I forwarded the same e-mail again. The response was as if I just sent it the first time - "we'll forward it to engineers". Two months after the day I've sent my first e-mail I got an update telling me that they want to invite me to onsite interview and that they'd contact me with possible options. It was three months ago. I contacted recruiter recently and told that I'm not interested in position anymore (I hoped to get any response - still nothing). So in total I've spent 5 months of waiting with no results and wasted two evenings while solving the interview problem.