Lenovo — Broke the phone instead of repairing

Address:	Khordha, Odisha, 751007
Website:	Lenovo Showroom Maharishi College Rd, Sahid Nagar, Bhubaneshwar, Odisha 751007

I submitted my Lenovo Zuk Z1 at Lenovo Showroom, BMC mall, bhubaneswar on 6th May due to issue in Battery. My phone was working fine and charging . It was getting shut down as the battery broke. They said they might need to change the motherboard which I felt unnecessary so I took my phone back. Now my phone is not even starting and not even getting charged. they Broke the Phone.
I need a repair/ refund of my phone as the issue was not there previously.