Faulty unit

I bought a 10\ tablet on 1 December 2014 from Computer Mania in Cape Gate. I had problems switching on the unit and 1February2015 I returned the unit because it didn't switch on and the memory card fell through the slot into the unit. About three weeks later they gave me a new unit. On June Friday12 I charged the unit and the battery was half charged when I switched it off. On June Saturday13 the unit didn't switch on. I then returned the unit to Computer Mania for a refund and they told me Mecer must first check the unit. I then received a call in that same week saying that I damaged the charging point