Hello Carlos,
You are protected under the Sale of Goods Act 1979, amended 1994, and Sale and Supply of Goods to Consumers Regulations 2002, but be prepared to put yourself out a little bit and do some writing.
If the fault occurs within 6mths of the purchase, your first port of call should alwasys be the retailer. Even after 6mths, you shd still go to the retailer. Dont let them tell you otherwise.
Most customer care/support advisors have no clue about the relevant legislatioin, have not been adequately trained, so its no wonder they would argue with you on these issues.
(1) Do not bother to argue with Customer Care or anybody
(2) Put all further correspondence in writing, and keep a record of iit - Email, and also send a written copy to Customer Care.
(3)Tell them whats happened, your experience over the phone. Quote the relevant legislation in your letters, and give them 10-14 days to resolve the issue. There are many template letters on the web.
(4) MAKE sure to send letters via recorded delivery - this is crucial.
(5) If no satisfactory ans from Customer Care, write to Head Office/Director /Ceo. In other words, escalate the issue. State the problem, the relevant legislation that protects you, their obligations under it, and give the 7 days to resolve or you would be taking it to a County Court. Usually, the issue would be resolved by/at this stage.
(6) If not, and you believe you are right, be prepared to go to the County Courts under Small Claims for it. Its not a complicated matter.
Remember, under 6mths, the onus is on the retailer/manufacturer to prove their is a fault, and not you. After 6mths, the onus (may) be on you. Furthermore, any repair,replacement should be done at no further costs to you - inc any postage.
Hope this helps.