Gear 2 endless issues

I got a new Gear 2 from Samsung at the wedge shopping center under warranty on during February 2016 and I have brought it in 3 times now because it doesn't hold charge. When they gave it to me it was dead and I queried why it was dead and couldn't be tested. I was told that it had been in the safe for some time and needed to be charged first. I took it and charged it to find it only last around 36 hours and that with it not connected ted tk the phone, with no notifications or anything running on it. I brought it back and a week later I came to collect it. I was told that they had to reload the software as there was a problem with it. Once again it was flat and I got the same excuse about it needing to be charged. I took it home and charged it fully and tested it again on Sunday to find that the battery is going flat way to fast. I called in and spoke to the manager who informed me to bring it in again. I am here now and get told by a messenger from the technician that the battery should only last 12 hours. I asked t see the technician and when he can I said I'm not a fool and I k ow it can last anywhere from 5 to 7 days. This is not acceptable on a new device