Read that end of "contract" email very carefully , if its the end of your first 12 months with Now then it will probably contain some "deals" if you agree to sign up for another 12 months minimum term.
If its the same as i had, and others have had then all of these "deals" will be more than you were/are on at the moment .
Lurking, hidden away at the bottom of this will/may be a do nothing option , I, and others have had this do nothing option which is the same price as the initial sign up , so by doing nothing you could well end up saving much more than actively renewing and signing up to a new minimum term.
The catch being that towards the end of this "offer" period, usually 12 months you may not get a reminder so you will need to keep a check on when the offer ends, as your monthly bill may double .
When you sign up to Now broadband, and almost every other ISP you sign up to a minimum term contract , when this minimum term period ends it goes to a monthly rolling contract, if you do nothing this is what will happen - the service will still continue however the price may change to a standard rate if you do not get any offers applied by default , so there is no need to panic as you will not loose your internet access/phone at the end of the minimum contract period
