Very nice case but strength problem

So I bought on June 12 this model and a month later the edge of the flap is peeled off. I thought it was a manufacturing defect but impossible to get a refund by "Destination Telecom".

I bought a second shell with flap on July 11, again via amazon in "France Passion 4 Mobiles GmbH" and again the slice begins to take off after almost a month of use.

It is a little expensive for a lifetime of one month.