Terrable rude customer service

I have a complaint about my battery being under warranty but not being able to start the car after filling up at the petrol station.

i took the battery back to the store where i purchased it (Lombard tyres weltevredenpark) and i was told its 100% and it was fully charged. I explained to the manager that i just drove the car back from woodmead after it was jump started and they said they cant replace a full battery. I then turned off the car and left the lights on for 6min and showed them that it wont start, and he then raised his voice and told me that i drained it. i then asked the manager that should not a standard battery hold charge for at-least 6min. cause essentially what i did is equivalent to what would happen if i were to be pulled over by a policeman at night. the shop owner then told me that a battery is only to start a car and not to have the lights on while its off. he then said that i should communicate with Willard directly to have my battery swapped out as its still under warranty.

Why sell me a product then give me warranty on it then later make it my problem to handle the replacement process