WiredTree Junior Python Developer interview questions

After applying online I was asked to interview in Chicago, a four hour drive from where I was living. They did not pay my travel expenses for this interview. I liked the office atmosphere, and the interviewers seemed nice. However, they seemed more interested in working while I was speaking than actually speaking with me or listening. I was extended an offer (no offer letter, they didn't do contracts) and given a 3 day deadline, but I was also interviewing with other companies so I emailed them and asked for a one-week extension to wrap things up elsewhere. I received no response to that email. The next week I asked if the salary was negotiable (admittedly I waited until the last minute to do it) and they replied saying my offer was rescinded because I didn't seem "long-term committed", and that they had sent me an email rescinding the offer back when I asked for the extension... but it "didn't go through." I'm still confused about why they would extend me an offer then take it away a couple days later, and I found the whole experience very unprofessional. I would not recommend interviewing here, especially if you have to travel for it.