Lenovo — I gave my lenovo zuk z1 for 20 days but they are not willing to give back

Address:

Kolkata, West Bengal, 700012

Dear sir,
I have purchased lenovo zuk z1 (Space grey) on may 19 from amazon.In in amazon flash sale.. After using for only 15 days i found a problem. The problem is no network detecting. On 17 june i submitted my mobile in hcl touch (Authorised service centre of lenovo) in kolkata, khairu place, cr avenue. They told me that it was a motherboard problem.. Today when i call to service centre the executives told me that they have not yet getting any reply from tecnical department of lenovo. Sir i just used my mobile for 15-20 days.. And how that motherbord problem occured? I just wanted to tell u plz replace my faulty product and give me new one or give me my money back.

Order id[protected]
Lenovo service record number-srin[protected]
Imei no-[protected]

I m gautam chowdhury i am the owner of this handset..
My mobile no is-[protected]
Waiting for positive reply.. Thanking you