Halo 5 Achievements not popping

I completed halo 5 on legendary solo all the way through when i was offline. When i got internet a year later my achievements never popped, i didn’t complain and i proceeded to complete it again. My achievement still hasn’t come. I have completed it on legendary a total of 4 times and i have no achievements, please help. 7135504133 (on my screen it shows it completed, i have screenshots to accommodate)

Same thing happened to me. H5G has horrible achievement registration.
Make sure that you’re online the entire time while playing the campaign. That did it for me.
If that didn’t work for you, don’t forget that the XBone itself can also glitch the achievements.
Occasionally an achievement is registered as being unlocked, but the console/the Xbox Live servers simply won’t have it pop.
It will unlock later by itself, sometimes with, sometimes without a notification. That can take anything from days up to months.
Sorry, I know that’s not what you wanted to hear, believe me, I’ve been there myself, but unfortunately that’s just the way it is.

Yes I am his uncle and I was on the phone with Microsoft technical support for the Xbox last night for 2 hours to the point to where they told me there’s nothing they can do on their end and when I simply reminder the man that was cutting me off and being rude that was the supervisor of the man I was speaking to that the phone call was being recorded on there end he said oh it’s being recorded and then he hung up on me I find the lack of care for achievements on Microsoft end to be a very massive disappointment and it has a big impact on the future of my gaming depending on which machine I will buy in the future weather be the PlayStation 5 or the Xbox series X I have been a fan of Microsoft since the original Xbox and I have spent countless dollars on their merchandise I’m an Xbox ambassador I’m signed up for the rewards program I’m an Xbox Live Gold Member I’m a game Pass member and the biggest functionality i care about the most is the achievements the rewards program is ran by the achievements and there are countless numbers of people experiencing the same exact problem originally Microsoft said when you log back into the internet after you’ve unlocked something offline your achievements would pop they need to address this problem especially for Halo 5 due to the fact that there are a lot of people experiencing this problem this is a very valid complaint that’s been noticed for years and nothing has been done I expect to see results here in the future this is also depending on whether I buy Halo infinite because it is a wasted point of time to focus so hard on the career of all the Halo games the Master Chief collection and Halo 5 to have everything for every one of the games and then come to a point to where one thing messes up and it messes up the entire series of games for the unlocks so this is my valid complaint I hope everyone that reads this has a good day