Occidental Petroleum interview questions

I submitted my application and had a phone interview within a day or two. They called me back to set up an interview for the next week. They seemed very eager to fill the position. I met with 3 accounting managers and a director. Then my interview ended with meeting with HR who kind of gives you a personality quiz. I was there for about 3 hours in total. The managers discussed the position and what it entailed and asked general questions about my skills. As I finished up with the director he told me that I had everything they were looking for. However they continued to still interview for a few weeks and got a system generated email saying the position had been filled. It was a bit frustrating because from everyone's comments I really thought I had the job. Also it was difficult trying to get a response from anyone about how the process was going. It also seems that despite what your told or the urgency that they took their time filling the position.