Kit Kat update

New phone...Samsung Galaxy core prime ...that came with Kit Kat 4.4..i read that this phone cam be updated to Lollipop 5.1...I called Samsung chat and they told me that i had to take this up with my servor, which is Tracfone. I was wondering, what would be the difference between each one to begin with, before I call Tracfone? On another gnawing note, I saw when I started to click on "Contacts", where i was getting ready to add some of my own, i came across a list that was so long of sorted emails that actually runs in the hundreds. Where did these come from and how to get rid of them permanently? I never created an Address list, in the event someone is going to ask.