Under the Sale of goods act, the retailer is responsible for up to 6 years depending on the item- the item must be fit for purpose, and of satisfactory quality. If they have sold it on a 12 month contract, then i is fair to assume that the iem is supposed to last for that amount of time.
Go back to them, taking a print of the act, and insist that they follow their obligations as legally obliged to in the act. If they refuse, tell them you will be writing to their head office, enclosing a copy of the act, and that you will also be sending the letter to trading standards.
http://www.berr.gov.uk/whatwedo/consumers/fact -sheets/page38311.html