Demaged Battery

Hi,

I Bought a Ford Fiesta 2014 at Imperial Mazda in Germiston,i was assisted by a Man by the name of Derick. He provided me with good service until the car battery started giving me a problem. I took it back to him,they checked it and said that it is fine,it just needs charging. 4 months down the line my battery is still giving problems, so i took it to battery centre. They said that the battery is dead, Derick was willing to help me replace the battery but his manager said i must have made it bad and its a wear and tear. But managed to replace my tires before i bought the car,which is also a wear and tear but didn't replace the battery which was more than 2 years old.