Bad service with **** products

Having a problem with the service i have received from Hi-fi Corp in Jabulane Maill. I bought a tv ( 48 intch carve Sansui ) cash on 24 Feb 2018 at the store they only switch on without checking a damage on it. 10 days after it was showing a line in middle of the screen and that time my tv was less than 12 days after i bought it. On 10 March Saturday i returned tv and they told me to buy another one that isn't repairable. But beg the lady from service center to book and she promised to do so, only to find out she did anything my tv was at the store room till now. Normally when book anything you receive an sms to confirm the booking ( Job number ) on discription paper stating is be wont repaired. They didn't even update me till i call them on the 20 March. What i want is to exchange or full refund for the iterm. There contact: ********** or email www.hificorp.co.za.