I have a Samsung S4 and the battery just started dying. It was confirmed by Samsung that my battery is swollen and it is a mistake on their behalf and they will replace the battery at no charge. I called Samsung in Century City and they then said that they do not have S4 batteries in stock, but if they get it, they will call me.
I called Samsung's Technical and Product support and received brilliant service from a lady called Mbeli. She told me that I could just contact Samsung in century city and provide proof of purchase of my phone together with the call reference nr she gave me (7112196628) and they will exchange the batter over the counter.
I then called Samsung in Century city and asked them whether they had batteries in stock. I spoke to a lady called Luanda. She confirmed that they do have the batteries in stock. When I asked if I can bring in the phone and replace it, she told me that I'd have to check it in and it is not possible.
I am extremely disappointed in Samsung's level of service as their members of staff did not give me the same message and I know have to settle for a broken phone because of their fault.