bad service

i took out a contract on a ISMART on the 29 January , I used the tablet for about 3 weeks then it just went blank , I called the call centre , they sent a courier to collect the tablet a week later , 2 weeks later I receive a phone call from one of the consultants telling me that the LCD was cracked etc etc , and that I need to pay R800 for repaires , this a a load of **** as when I question the technical department to ask them how the tablet was tested etc they couldn't actually tell me , they gave me the run around & I even left messages to a manager to contact me , up until today no one has called me , Really **** service , now I am paying R340 for a sim card with 500megs data and still have no tablet . what the hell , I was even prepared to buy a new device at a discounted price , its now 2 months and still have no tablet ,