no DK questline

I did this whole thing twice and still does not work, after creating DK, and completing quests : killing citizens, getting 15 arrrows, duel 5 DKs and after getting mount, there should be Q from Prince Valanar, to speak with Gothik the Harvester... but there is nothing, i thought , ok it is bugged, so i deleted character and created new ... and same thing happened, i can not continue in playing, cause, there is nothing to do

Have you completed the quest Abandoned Mail quest#12711? You can find it in Havenshire (the area right below Death's Breach) on a mailbox next to one of the houses
https://wow.gamepedia.com/Death_knig...ing_experience

did not , thank you