Standard Presta Valve Tube

Sierra Bicycle Supply responded to my complaint in less than 2 hours and issued a refund for the defective tube.
This indicates to me that they are a good customer-oriented organization.

ORIGINAL COMPLAINT:
Both tires and tubes were well packaged and arrived safely. (All Condition Armadillo 700X25 and Standard Presta Valve tube 700X20-28C) I installed them and pumped them up with no problem. The next time I went to ride, the rear tube valve had a substantial leak. Loosening the nut and pressing the release pin resulted in a loud air leak that does not stop when I release the pin. The loud leak appears to stop when the nut is firmly tightened. I don't trust this arrangement.