Cannot unlock Rey's Resilient skin

I am having a problem with star wars battlefront 2 on xbox one, I am trying to unlock rey's resilient skin , i searched on youtube how to do it. When through all of the instructions did my best to do them all correctly, when I did the final thing that was open the door went in the room the calls to you milestone showed up on my screen. I thought that I had unlocked rey's resilient skin so I wait until the end of the match and I also did all of this in a co-op mission but to continue I waited until the end of the match because I was afraid that I might lose it if I just quit the match early so I waited. after the match was over I was excited to see if I had unlocked but to only find out I didn't and I didn't understand what I did wrong, I had followed all of the instructions, also wondering should I try again to see if I did something wrong but I have not try again. I did talk to customer service and they thought I should bring it to forum so I just wonder what is going on and why it didn't unlock, did I do something wrong or not follow instructions. I would really appreciate any comments to help me unlock this or understand if I did something wrong? 

[Hero edit: changed title to be more descriptive]