Willard batteries not keeping their word.

I purchased as willard battery at their branch in President Steyn in Pretoria North, with a warranty of 25 months. The battery gave me some challenges and i took it to them. Left it for a day as advised and they borrowed me a spare one. I returned the following day and only to be informed that my battery had died completely and i will be given a new one once the representative has been consulted. It is almost two weeks now. I got a call and now the tune has changed because they blame my carbs alternator as the cause. All i want is my new battery. At point of sales i was never informed of other causes. They said should it fail,bring it back and we will give you a new one.