Poor quality of shorts material

I bought a pair of shorts from Cape Union Mart, Gateway in November 2014. I have had to return these shorts because the press studs on the pockets would tear out after approx two weeks of wear. I have returned the shorts four times already and I have been given a new pair every time in exchange. But every time the pocket material, where the press studs are located would tear after approx two weeks of wear. I have now been waiting two months for a replacement. But the problem is the material of the shorts which would appear to be too weak support the press studs.