Fon Wireless interview questions

I went thru a whole set of 7 hours interview (1 by phone, 6 in person) with different people in the organization. They told me they would call me back in 10 days and they never did it. I contacted them twice and after a month they answered me back. They told me they would call me the following day to talk about other opportunities in the company and they didn´t call. I think that is not serious way of handling interviews.