Lenovo — Complaint against Lenovo Smartphone Company and Lenovo Service Centre

Address:

Kolkata, West Bengal, 700124

Sir,
I use a smartphone of Lenovo a7000a since April 2016. But on 26th October, 2016 my phone was neither switched on not getting charged. That's why I have visited the nearest Lenovo Service Centre On 27th October at Cybernitics Infotech, which is in Barasat, North 24 Parganas, West Bengal. After they cheked up they told me it was a issue related to mother board, and they need to keep the phone with them, they will returned it within 15 (fifteen) days. So I submit my phone to them. As my phone was in the warranty period, So it would be free of cost.
But it was day by day, weeks by weeks neither they call me, nor they have given me any info. So I called them on 17th of November. But they told me they need another 2-3 weeks. But again after I called them on 26th of November. But they misbehaved me on the phone and told me that they haven't received the parts so i need to wait till they call back to me. But they didn't tell me within how many days I may get my phone.
And My experience with the Lenovo Customer care was worse more. Even they also telling me to wait, but they cant telling me when I can get my phone. And also I have lost my 1 month of warranty.
So my complaint is against The Lenovo Company and also against the authorised Service Centre.