CoD: Modern Warfare 3 on 360 achievements not unlocking.

I apologize if this has already been posted about. I did a search and didn't see anything that fit what I'm seeing.

So I know the game is old however, since i've had extra time, Ive been playing my 360 CoD games on my 360 console. Ghost, MW2 have been working well. I first started completing the remasters on XB1. I thought why not play the 360 version on my 360 console.
I was able to get thru MW2 360 fine and complete all the veteran missions and got all those achievements for MW2 360.

I then started with MW3 360. I start and go thru Act 1. I was able to get the first combo mission on veteran fine.

Then I started on the following combo achievement:

Payback

Complete "Mind the Gap", "Goalpost", and "Return to Sender" on Veteran difficulty.

I got thru the last mission and while the next mission started after Return to Sender, I did not see Payback achievement appear on the screen.

I was bothered by this as it take some time to get thru these missions on this difficulty and didn't appear to pop.

So I played then again and still the achievement didn't appear after the 3rd mission was complete on Veteran.

I kept going and the next combo achievement appeared for me when the 3rd mission completed:

This is the End

Complete "Scorched Earth", "Down the Rabbit Hole", and "Dust to Dust" on Veteran difficulty

So I though these 3 missions worked.

So I thought maybe the installation of the game was bad. So i removed all MW3 files and the game from the console then restarted the console then re-inatalled the game from disk again. There was a small update to the game and was applied successfully.

I then attempted to try the following achievement as I presumed if I played these two back to back on veteran it should work:

City of Lights

Complete "Bag and Drag" and "Iron Lady" on Veteran difficulty.

Played all the way thru both missions and got to the end of Iron Lady and then the next mission started. Still no achievement.

So I have now done the following:

If you're on Xbox 360:

1. If things still aren't looking right, give the following troubleshooting steps a shot:
   • Delete your profile ONLY (do NOT delete profile and items).
   • Clear your system cache.
   • Restart your console.
   • Download your profile.
   • Attempt to unlock the Achievement again.
2. If the achievement is showing as unlocked, but you're not seeing the Gamerscore from the achievement added to your total Gamerscore and the unlocked count for the game in question is incorrect: Head over to your profile on Xbox.com, view the game and achievement
   in question on your profile, then wait a full 72 hours for things to process.

I will give this a try later today and see if anything changes. #2 for me is that the achievement is not appearing at all after the last mission completes for these two achievements only. I'll report my findings.

Question is, should I do anything else to see about these two achievements not appearing after the missions are done? Hoping to ensure once I do this that the achievement will appear. Seems like all the other achievements are working. I just got the "No
Assistance Needed" and "50/50" in spec ops today which did appear and was counted for. Odd that these two combo achievements are not appearing. Kind of a waste of time when I go thru the missions and complete them and the achievements don't pop. Which also
prevents me from betting the final Best of the Best achievement.

I suppose I could try this on my XB1 console as well. Just think that if the other achievements appeared on the 360, these two should as well

Please advise.

Thank you for your time.

:)