Bad service and unreliable returns

I bought a car battery at Super quick in Amalinda. It has been giving me problems since day one. I sold this battery under a 2 year warranty and now that I want to change it the manager claims that there is nothing they can do. I have not been anywhere to ask for assistance regarding the battery problems but I have been visiting Super quick and they kept charging it. Now that they’ve done a battery test and see that something is wrong with the battery they refuse to honour their warranty details.