Sangyon Pick Up 4x4 truck

I have a 2014 truck but with only 20,000 km.
Recently it presents a difficulty to pass the change.
In the official workshop they are telling me that there can be a malfunction at the clutch level and that to finish diagnosing the workshop, the official workshop informs me that you have to disassemble the exchange box to define whether it is guarantee or not, since the clutch is an item of the vehicle that does not enter the guarantee since it is an item that is subjected to wear by use.
The truth is that I do not understand how can be a wear for use since the vehicle has only 20,000 km and according to my point of view it is a factory defect.
The question is as follows: how can I prove that it is a factory defect?
Thanks for eventual answers.
Cinzia

Hello Cfrigo: Consult in the Serv.Oficial if your model has a bima clutch, since if it were the most disastrous invention of the automotive engineers. It is preferable that you change to conventional clutch that Valeo offers for each brand. If it was not bimasa you do not pay attention to this post

Thank you very much! You really gave me very precious information!

Thank you very much! You really gave me very precious information!