Since when!

I want to know where it states that your charger only has a 6 month warranty in the documents you receive with your phone. I was just turned away from the Samsung store at Constantia because my tax invoice has 22 July 2015 as the purchase date. My charger is faulty and when tested it was confirmed that it is the actual charging plug yet I am now told that everyone should know your charger has a 6 month warranty!! Are you telling me that I will need to buy a new Samsung charger every 6 months for my phone!! And then the technical manager at samsung tries to tell me that they start counting from the beginning of July for the invoice! why? I didn't purchase the phone on the 1st of July!!! Both myself and my colleague had the same problem with our chargers so OBVIOUSLY this is a Samsung fault.