Exploding Gas Burner !!

I had the frightening experience this morning when a Alva single burner gas stove literally exploded in my face, burning the hairs off my arm. The (obviously) sub standard device was purchased from Builders Warehouse a while ago but had only been used a handful of times. I returning the device immediately to Buiders Express, Cresta. The 'manager' informed me that without the sales slip he could not help me !! I instructed him to keep my 'loyalty' card and the highly dangerous burner and that I would NEVER support Alva or Builders again.