Lygoworld, poor Turtlebeach repair experience

My son bought a Turtlebeach headset from Amazon with his Christmas money. He pretty much spent all of it on this ~£100 headset only to have the microphone fail a month later.
Lygoworld handle the headset repairs in the UK, and they insisted we send them £25 to cover the damage in addition to the £7 it cost us to send the headset back.
More details once we get the headset back after nearly a month so far.
I'll also be interested to see what Amazon and Turtlebeach themselves say.