Hot Seat and Express Boarding???

During the flight back from KL to Brunei, ani yg happened, bought the express boarding but not applied as people just ask to enter by the airasia staff without calling for express bording to go first. it was supposed to be people on the right side with express boarding and on the left with non of it. but still dats ok coz i think it was not a big deal coz we already have the Hot Seat booked. Then on the plane I noticed the hot seat were not full and behind us there wer two rows empty. I thought this gonna be a long but quiet and peaceful flight. Then as the plane took off, and the seat belts signs were off I was surprised to hear lots of noise behind me. I look back and found out that the seats were taken. So my supposed to be peaceful and quiet flight was shattered by the noise made by them. If only the flight attendances were strict enough to not allowing them to sit on the hot seat. I feel cheated as we have to pay to get that seat but they didn't....