Kanex XD stopped working today.

Hello,

I have had a Kanex XD for around 7 months now, and today it has decided to give up on me. The XD just wouldn't find a signal. The blue light next to the Minidisplay port wouldn't light up blue, and the iMac just kept popping out of Target display mode back to the iMac interface. A few hours later I tried and it worked, but then wouldn't work again.

I've checked that I haven't installed a firmware update that would make the Kanex stop working, so I really dont know what to do. I bought it on Amazon and have tried to return it but it only had a 30-day returns policy!

Thanks in advance.