Cant Earn achievements

But that one achievement cant be earned off line

If your account was compromised you need to contact phone support to open an unauthorized access case. But as stated above if your GS has been reset there is no way to earn the achievements you once had.

yeah all they can do is remove the CHEATER mark the only way to get your old score back sadly is to create a new account and start all over again.

Delete your gamertag, then re-download it at console. Then clean cache.

From everything I have read in the forums in the past, once you get reset, I have learned that all achievements that were wiped away cannot be re-earned on that same account, whether they were previously earned legitimately or not, or are now attempted through
legitimate means.