Eastvaal Motors Ford sold new Mustang with faulty battery / starter.

I bought a new Mustang in Dec 2018, in May 2019 the battery failed, normally this happens not even when the car has been standing; normally I will stop for 30min then it fails to start makes one wonder if it is even the battery that is faulty. First incident I reported it and they came to jump-start, claiming I am not using the vehicle as often although it was only standing for 2 days and already sitting at above 5000kms. I have since had to jump-start the car for about 7 times since then. I have spoken to my sales person since then and sent her an email 10 days ago without any help. Surely the battery cannot have less than 6 months warranty or whatever is wrong with the car.