Acute ultra aggressive and sibilant defective copy?

Can not listen among others the latest installment of Arcade Fire without ears bleed Despite 3 weeks of use (and thus break made if running there) and despite having carefully chosen the most suitable caps to my ears, the sound issued by that-ear remains desperately unlistenable I have to turn down the volume on full songs, full albums on because even at normal and reasonable volume treble will be ultra aggressive and sibilant A torture for the ears!
This is my first Sennheiser which is nevertheless a very famous brand and I do not understand because I have never had a similar problem with my other ear headphones (including amounts Klipsch well). So I naturally thought of a defective copy, and I sent an email to Sennheiser France. They replied, "The mm70i is not a high-end product can deliver outstanding sound If you want great value for money product, I highly recommend the Momentum In Ear."
Conclusion Sennheiser France my copy is not defective and that is normal for the MM70i still sold within 75 unlistenable is visibly Sennheiser France considers that to have a helmet that does not make ears bleed you need to type in models yet more expensive
I had a lot of in-ear headphones, much more expensive (250) and much cheaper (30) and I have never had something as unlistenable
I recommend with the greatest force this model.