I was just a victim of hacker wallet (MEW), is there any way to overcome it, or find out who this person is, or can we recover what has been stolen .. ?? 
You can't do anything because basically, it's permanent and not reversible. Just forget it and it's really difficult to find who is the real actor behind this story because everything in the crypto has encrypted by algo. Even coincheck can't reveal who was stealing a lot of nem coin after some investigations.