Item not repaired

I purchased a Samsung J1 cell phone in February 2016. After a week it began switching off on it's own for no reason. I then had to remove the battery and replace it every time to reboot it. I took it to the service centre in Canal Walk and it was sent to the repair centre. After receiving it back I had to re-install everything which was a real inconvenience but it had not been repaired as it went off during the same night that I received it.. I wonder whether anything was even done to the item.