Why does my old MSN address get synced instead of my gmail address

It's just something that I find pretty annoying and have no idea where it comes from. When someone add me to their contact list, it automatically add my old MSN email address (that I was using 10 years ago) in his contact info, instead of my gmail address. Why is that? Where is that address coming from? Why is google retrieving a MSN address instead of gmail? I haven't used this email in the past 5 years at least and this is not the email used by Facebook.