SOLD ME A CAR WITH OLD BATTERY

I have bought my kia rio that was delivered December 2017. In January I was jumped and I thought it was the charger that consumed the battery. By now I have exhausted my kia roadside assistance and been told to take the car to kia where I was told my battery is dead I therefore need to buy a new one. I have contacted imperial multi franchise diep river they told me they are not liable, it came to me as a shock. I have just bought a new battery for a 34000 km car that arrived at 29000km. is this what kia delivers to us as clients. imperial has been a mess from the word go I would never ever go back. I NEED TO UNDERSTAND THESE TWO.