Bullets will not stay in magazine - ProMag Sig Sauer P938 9mm Luger Pistol Magazine

I purchased 3 magazines for my SigSauer P938 The bullets pop out of the magazines. I set the magazine on top of my bed comforter and all the bullets popped out. The magazine discharged all of them. I tried all 3 magazines with the same result. I have also had malfunctions with magazines at the shooting range. Do not purchase these magazines.