I had purchased my pair from a member here, had no proof of purchase, and they were too old for any warranty claim. I contacted Vsonic in the hope they could help me, I stated all of the above and requested/pleaded for a repair and would be happy to pay for it. They requested I send them in and they would review and let me know....good start!
The only bad point to this story is the large passage of time where I believed them to be stuck at customs in Beijing, to the point I had filled out a Royal Mail claim form. Anyway, approximately 6 weeks after sending them I got a confirmation email saying they had been received and they would be fixed by the end of the week! Good times! This Sunday I got a text to say they had been shipped and they arrived back fully working yesterday! I've had to chase them to see if they wanted any payment for it, the repair was free and they have only requested covering the freight.
For those interested the fault was the driver had come loose from the casing (these have had a few miles on them so it makes sense). For those with a similar issue, and you don't fancy the wait and don't mind voiding any warranty, you could separate the casing by heating it up (I've seen a guide on here somewhere) and doing it yourself.
I think this is a great example of customer service.