LinkedIn interview questions

I applied the position through Linkedin. After 2 months, they called me and ask for the interview date. Only after 2 weeks we had a phone interview. It was very easy, she asked the standard interview questions. The Interviewer told me that we had a nice conversation and I would get a feedback in a few days. Then she hasn't responed for 1 and half week. I sent an email her about the application status and she said that I had a successful interview but they were considering an internal candidate for this position and she would get back to me for the next steps. Again, I waited for 2 more weeks without any answer. After 2 weeks, I sent her an email whether they would continue to the recruiting process or not; the interviewer told me that she forgot to answer, they have decided to proceed with the internal candidate.It was very disappointing that Linkedin, one of companies that I admire, had such a unprofessional recruiting process with no respect to the candidates.