Xbox one achievements not unlocking

I’ve come back to clean up the achievements on far cry 4 and it happens that one of the achievements that I tried to unlock isn’t unlocking, I know for a fact that I’ve met the requirements for the achievement. The achievement is Trigger-Man, which requires me to complete 3 assassination or eye for an eye quests. Not only I’ve completed 3 of these missions, I also did 3 more to make sure that the achievement is glitched. This is the sixth achievement to glitch for me across 3 games. I’ve already done all the steps Microsoft supports asks you to do, I’ve tried to get a fix for my problem by Twitter, but the staff just stop answering me, which I think is just outrageous to stop replying to a customer and also tried to get in contact with Microsoft support on their website but they never got a definitively answer, they tried pushing me over to true achievements, which doesn’t have anything to do with Xbox’s achievements system, and also said that my case was forwarded to the right people at Microsoft, but obviously nothing happened. I would like to have my achievements fixed, I have more then enough proof to prove that I have met the requirements and that this is happening because of a **** achievement system.

:)