Car battery replacement

I'm so ****ed at cartrack for their bad service that I have been getting from them. I bought a car battery from them in April, but now the battery is not charging and I cannot use my car to travel to work. I have been sending them emails since Monday however no assistant, Thulani Mafenuka advices he will send me an email and that was Tuesday and he has not, I called today and they said his not available and I cannot even speak to his manager but I must send an email. I need a new battery or a refund as it's still under guarantee 😡