Ignite refusing to work!!!

so last game of hexakill i was vs a Yi as kog, he would alpha in i would unload and ignite him <i knew it ignited because ignite went on cd>, but it being yi and cheese champ i would die but he would run off after kill without ignite...... but after he killed and took off my ignite would pop off cd <the instant i died>.... like i never used it at all but yet it went on cd when i used on him...

rly riot....