Multiple Achievements on multiple games will not unlock (Since April)

Hey there, I've contacted Xbox support many times to solve this unusual issue of Achievements not unlocking. Firstly, i've done alot of research on this issue and i've tried many things to fix it but with no luck. I've submitted a survey for this issue as
told to by a support member, but i want to make sure that this issue is at the very least being addressed.

Next, to help add information to this issue, the achievements that aren't unlocking on many different games, are affecting all of my other Xbox Live accounts which is incredibly strange. After telling 2 support members about the issue they agreed this was
the best place to help me fix my unusual issue.

Thanks in advance,

Regards,

Will (GamerTag: )

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:)

 

"Personal Vendetta" Assassin's Creed is not unlocking

I've completed the requirements for the achievement multiple times, with multiple discs, on multiple consoles and it won't unlock. Please help.

Case# 1253594428

 

Since Aug 26th My Xbox One achievements won't unlock

So since the 26th i played multiple game's where i should get achievements, i tought at first i had the bug where i should wait 2/3 days to unlock them, but i don't the achievements are not saying unlocking etc and it are not bugged achievements i even redo
the requirements to get them to unlock and i won't get them i did multiple hard resets etc but still no luck :/