HDJ-C70 Broken Driver

 Hi,

I have had my headphones for 8 months the last 2 of which I have been unable to use them.  The left driver has stopped working and does not produce any sound.  I am told they cannot be returned as I bought them from amazon and the original seller will not answer my emails so Pioneer wont take them back despite being less than a year old.
I paid a lot of money for these headphones, is there anyway pioneer can provide me with a left driver I am happy to pay and repair myself.