The interview was smooth. I got the offer on the phone after few days and HR pushed me to reply in 2 days. I took the offer and the HR told me to wait for the start day which wasn't confirmed. I tried to call and ask for few times, either the HR was meant to avoid my call or just kept telling me to wait. I asked for a confirmation for my offer, they said no but only employment letter once I started working. It turned out the offer they gave me wasn't confirmed and they were still waiting approval from the headquarter. Both HR and department head promised to call back and update me for details but they never did. They never sent me an email and everything was on the phone so I don't have a proof for the offer. The whole thing was so unprofessional and ridiculous. Especially I turned down another offer for this one. I tried to call again 3 weeks after I took the offer, there was no answer as usual. They finally called me back and gave me excuses like the management have problem with the headcount and the employment process couldn't go forward. They only left me a sorry and ended the call. This is totally unbelievable for such a big international company handling things in this unprofessional way with no respect at all.