Pathetic Kulula.com

I booked tickets on 23/11/2017 for valentines day 2018. I am claustrophobic so I pre-purchased 2 tickets at the front of the plane. When online checkin opened 13/2 the pre-booked seats were given to other passengers without notice. ‘Different plane’ was the answer? On both legs of my reservation LFUOJK. How long are we going to allow Kulula to get away with this. I made this booking via Discovery Vitality...and it detracts on the general service and brand of Discovery the company