Update on the Kirisun - bit of a problem

Well, today I turned on my Kirisuns again, and was trying out the messaging a bit. I turned the volume up on one radio and sent it a message, and the audio went!
After that, there was no more audio coming out of the speaker when I pressed buttons, sent messages or voice calls. Very annoyed with this. I think kirisun will need to sort out this problem. Other people have said that their audio has broken too, but no one else I know of has had this happen just by turning the audio up all the way. It happened to others if they plugged in the programming lead with the radio on.
I'm going to try to get the radio replaced or repaired, and hope that the other radio doesn't produce the same problem.
I've tried turning the radio on and off, even removing the battery, but still to no avail. I think it's definitely a hardware fault.
Chinese manufacturers really need to get their act together and properly test their products before selling them to people.