If there's one thing you should always remember about science, it's that fact and truth are established after multiple studies converge on an answer. Even after that, further research might turn over what you thought was true of the other studies, because you were looking at it through too narrow of a lens. Single papers offer evidence, but rarely do they offer firm truths.
Vodafone is making big, big changes to the way it operates. Two-year lock-in contracts for mobile plans are a thing of the past, and you'll no longer be locked in to ongoing handset repayments either. you can buy a new phone outright, or pay it off over 12, 24 or 36 months.