Billed for phone that is no longer used after upgrade

<p>I upgraded my phone on the 15th May 2017. I received the June invoice and now I'm paying for 2 devices. I called your call centre and was informed that this was because I upgraded but that me previous contract wasn't finished yet, so I have to pay the previous device for the last 3 months of THAT contract as well as pay for the new device. I was not told that upgrading my phone 3 month's early (as its allowed by you) would mean I have to pay for 2 phones the last 3 month's of my previous contract.<br /><br /></p> <p>Now I'm paying for a phone that I'm not using. If this was explained to me on the day that I upgraded, I would not have taken the new phone. This is not the first time that I upgrade and I've never before had to pay for the 2nd unused device before. If that is the case, then you shouldn't even allow people to option to upgrade to a new device before the previous contract has run its course.<br /><br /></p> <p> </p>