At some point, all my live.com contacts have got duplicated so for instance John Smith will appear in my People hub linked against his FaceBook, Twitter, and two (or sometimes more) Outlook contacts. These duplicates are all phone contacts, originally from a SIM before I got my Lumia, that were migrated to my live.com account when I got the phone. I think it happened when I was running WP 7.x.
I've checked online in my live.com account contacts, and it shows all my contacts having the same duplicates there two so it's not just on the phone - I recently reset my phone and the problem persists.
It is mainly annoying because everytime someone has a birthday, I get 2 or more notifications at the same time since there are duplicate contacts with the same birthday.
Is there any way I can address this without manually going through every single contact? I can't even wipe my live.com contacts (I think) since they're not stored on the SIM and would all be lost.