Worst service and product

I bought a Telefunken tablet on 14/12/2019at Hifi Westgate , only to get home and find out that its dead and not working, went back on 15/12/2019 and iwas given another one by the same consultant who gave me the dead one and i got home other letters are not working when typing. What should i do now. All of their shops dont answe phones, even their call center. Worst service ever, i want my money back and to the public never buy at any hifi corp shop unless you feel like throwing your money in the bin