Sold Damaged Goods

I phoned the branch and inquired on whether they have batteries for a Samsung Galaxy S4. I was told that they do have and that it costs R300. I asked if I can send someone to come and pick it up and if I could pay by EFT. The answer was yes I can send someone but no I can't pay by EFT. I gave my employee my card then and he went and purchased the battery. Two weeks later the battery does not last 4 hours. When I took it back I was told that there are no warranties on batteries if the store does not fit and test the battery themselves. I was never told this. Okay, they say they told my employee and he agrees but says he told them that he doesn't know he only came to pick the battery up. Now I am being told tough luck, I need to buy a new battery (at least at a 10% discount, WOW), they will send send the dead battery back to the suppliers and be refunded for it! Not me, the store! If the lady answering the phone had just told me, I would gladly have sent the phone along, but I did not know. I really feel cheated.