Bad service @HiFi-Corporation mall @carnival

I bought Hi-sense tv 55 inch on the 27th of November 2019 at Hifi-corporation Mall @ Carnival it costs R7999 and it was not the only item I bought few items with the total amount of R9037.80 and i was with my mother who swiped her card since she wanted to buy me something for Christmas. The cashier that assisted us swiped the bank card twice and asked my mom to enter pin twice and the transaction went through twice and gave a lame excuse when asked why she asked my mom to enter pin twice. The transaction went through twice ,instead of paying R9037.80 ,my mom paid almost R20 000 and it took my mom to drive back again with her own petrol the following day for a refund.Yesterday the tv started to show a straight across which was weird. This morning I called the store to complain and I was told about 14 days return policy and repairs which i dont understand because the tv was fine until yesterday and i did not know it will be like this after 14 days. The lady was rude and kept on referring to 14 days policy.I don't want the tv to be repaired,I want a brand new tv because the one that was sold to me was faulty and I don't want it anymore. This is a sign that they sell faulty electrical appliances. This is not the 1st time because early this year around March I bought a laptop and found that buttons were visa versa but I did not raise it as an issue because I marked the buttons correctly but now this is a confirmation that they are selling faulty electrical appliances. I'm so angry and disappointed I should have gone to Makro I always receive best service and their appliances never gave me a problem.