damaged battery

My husband bought a maxim carbattery from Grabouw tyres for R1000,00 in September 2015 and the battery has a 2 year guarantee. When he put the battery into his vehicle it did not want to work. He went back to Grabouw tyres to exchange the battery 3 times but they sid not want to replace the battery or refund him. The rep from maxim batteries also did not want to replace the battery. Maxim gives a 2year guarantee on their batteries. I want a new battery or a refund. Very bad service.