Iberia Airlines - IB6843 had a 6 hours delay
 

We had a flight with Iberia from Madrid to Buenos Aires and there was a 6 hours delay .We did not get any accomodation or compensation.We were all the night (9hours)in the airport

You need to give more details. What was the cause of the delay? Also, your numbers don't make since. If the flight was delayed for 6 hours, then how are you spending 9 at the airport? Sounds as if you spent 3 hours there after the plane left.