Terrible service

I have purchased a car at VW Menlyn branch this year January and i have owned the car for 5 months and the battery have died. I phoned and emailed the Sales Executive guy who sold me the car hes been ignoring me. i then phoned his manager and he told me straight that they gave me a car when the battery was working so its not their problem that the battery has died. i mean how can the battery lasts for 5 months. Getting that response from the manager is really shocking. i am so disapointed in VW especially the Menlyn Branch. All you want is people's money while your service SUCKS. i am really angry and i wish people can go to other dealers and distance themselves from this TERRIBLE service.