Sound Select JHB Defective Loudspeaker Unit

I purchased 2 Wharfedale 8" titan speakers only to find that 1 of the units gives off a distorted sound. It was sent back to the "technicians" for further inspection with an all clear that the unit is in working order. I travel quite a bit, the items reached me a week and half later during this time I could not test the unit to verify that the distortion is no longer. Upon my arrival at home I tested the unit only to find that the speaker still distorts! I have subsequently asked them to refer me to their manager but to no avail. I requested that their technician come to my address to test and hear the actual distortion, but obviously they couldn't bother replying to my email. Poor service!