fnb conexis x1

my wifes device x1's battery exploded in her hand and she then dropped the device from shock i went to the strand fnb branch on the 6th of February to notify and find out what to do they then sended of pictures of the broken device to the supplier and arranged pickup of the device however on the 8th of February they contacted me back saying the device is excessive damaged and they wont repair or replace the device the battery exploded and it was a factory fault not my wifes fault i still have my 1000 rand invested in their account and would like to know what is the next to be done obviously its a weak product and my wife could have been badly hurt please sort out this issue