I am pretty sure I read that GM's don't deal with achievements or loot. Was like a year ago when I read a response on something to do with this. So it was very low priority and probably placed aside. Because as you said you did the kill again and she got it. What was so hard about that? And if it was a bug report like that they would of told you to post it on the forum anyways, or place a call on the support page. They don't deal with those things in game, they do deal with harassment or drastic problems on abuse on or by players.
Also pretty sure they would of told you if they did respond, Try the kill again and if it repeats then report it.
Sorry about the trouble but they don't have questionable habits as stated and known. the rickrolling and fun time GM's are for the no save game to give some livelyness in the event. I think its awesome to have live team's in game interacting with us.