Defective APC UPS

My new 500 VA APC UPS gave me an electirc shock when I touched the computer. The company fellows replaced it with an old unit. And, Lo, the old unit also was defective. It supplies electricity thru without be ing switched on. It seems that there is no quality and safety control in their manufacturing unit and there purchase should be avoided.

Dr. A.R. Chaudhri, Chandigarh