Creaking noise from a MacBook Pro 2014

Hi,

Since a month my MacBook Pro mid-2014 makes a creaking noise when I hold it in one hand or when I put my hand near the TrackPad. I took it yesterday to the Genius Bar in Lyon Part-Dieux and they told me that it was normal, it was a little assembly error but Apple would not consider it as a big problem.

After a bit of arguing, the Apple Store agreed to change the aluminum shell, but they said that they are not sure that it would help to solve the problem ... I'm now upset considering the price of this computer and it makes the noise of a very very cheap computer. What do you think I should do considering that the Apple Store has no solution ?