Second hand phone on a price of a new one

I bought a new phone on Sunday the 27/10/19 at pep cell store number 4961 the cashier who assisted me was Lebo the fine had network problems at first they said Telkom has a problem .went back on Wednesday with the same problem still was not assisted.went back on Sunday n was told that my guarantee has expired Nelly was helping me n she called the store manager and she said she is not working on the day......i went back today n asked for my money back they said they can't not do that spoke to Almor today who also could not help.....explained all the faults the fine had a new phone with a battery that gets hot when being charged, apps not responding, network not connecting this phone is barely a week old and they want to book it for repairs......i feel like I've been sold a second hand phone on a price of a new one their costumer care could not help to