Sorry if there is already another topic on this, if so please direct me to it.
I have completed all missions on legendary (alone), but it has not given me the achievements for it. I'm not sure exactly why this happened but there is a very complicated story behind it. If anyone is willing to help I will gladly share the information. I would just like my achievements and for it to show that I have completed it on legendary on my Reach service record.
Note: It even says I have the achievements for completing all of the missions on normal or harder.