S4 Battery swelling up

My battery of my phone is swelling up again after i replaced it a year ago. I just spoke to a consultant who stated that I have to go into a service centre which is going to cost me money to replace a battery and this a a manufacturing fault. first of all its an inconvenience to me to go to the service centre when the previous battery was delivered to my doorstep, secondly I am supposed to fork out R450 for a battery that will swell up again in a years time? i was previously very impressed with Samsung service in this regard as the previous time they helped me quick and efficiently. Seems that changed very fast...This is seriously making me reconsider my decision to get a Samsung again when my contract expires