Vampire Wire Xhadow XLR Plug MULTIPLE DEFECTIVE PLUGS!!

I recently placed an order for 8 Xhadow XLR plugs from the Vampire Wire online store. I received them and they worked great initially, but after plugging and unplugging them about 5 or 6 times over the course of a week or so they became easier and easier to slide into place and then the female ports started losing contact and the channel dropped out or was down by at least 20db!!!

I have been using Neutrik for about 20 years and have NEVER had a plug fail, whether at home or in the field. It seems the copper female ports are too malleable and lose their "springiness" too easily and lose contact with the male pins. The chassis connector is a standard Neutrik one, so nothing fancy there to possibly mess this up. 

They already said they will refund the money when I send back the plugs. What I want to know is if any of you guys have had durability problems with these plugs or similar designs, such as the ETI, etc?