Lenovo — lenovo k6 power 4gb 32gb

Address:

Lakhimpur Kheri, Uttar Pradesh, 262701

I had bought one android lenovo k6 power dated jul-2017 on line via paytm many times repair/replaced parts at lenovo center last time replace pcb by lenovo center, lakhimpur (Kheri) while network issue regular than last 1 month before updated the system by center after update network issues missing complete. After that open the handset and told me burn pcb. This set is not covered in warranty.
Why so not coverd in warranty while my set pcb burn by lenovo center lakhimpur kheri up pin -262 701. Service vendor - mr rohit gupta (R k) which mobile number is [protected] told me this set is not covered in warranty.
Plz look into the matter and take necessary action.
Asap