Unwillingness to refund

I am very disappointed with your service, specifically with regards to your store in Cavendish Square. In December 2014 I purchased a set of JBL E40BT wireless headphones. Less than 6 months later, the right ear was faulty and failed to work. I then took it back to the store to have it exchanged. Once again, less than 6 months later, the left ear failed to work and I attempted to return it to the store in October this year in order to get my money fully refunded. I received horrible customer service upon trying to get my money back. Initially I had to go to the bank to get a statement proving that I had purchased the product, as I did not have the receipt. After this, the headphones were booked in for an assessment by a JBL rep. I followed store policies, all the while being led to believe that I may have the possibility of getting my money back. As of today, I have been told that I cant get my money back as the unit has exceeded the 10 day warranty (of which I was not informed). I have been insulted by staff insinuating that the fault is due to my negligence. I am deeply dissatisfied and exceptionally frustrated with the lack of respect, assistance and negligence shown.