replacement of car battery

I purchased a car battery which after testing had dead cells and it was replaced problem with the replacement battery was that it swelled so much that it could explode at any time by taking this difective battery back AGAIN I was told that the warranty of the product is from day 1 when the original product was bought which according to me is incorrect because this is a sealed unit and the replacement unit was also not working as advertised so if this is the way that brights plattekloof handles customers. going forward I would rather buy from businesses where money is good enough for the working product my advice would be rather stay away from companies that except my money as good enough but to reluctant to back up their product