Xiaomi India — motherboard locked by mi authorized service center

Address:

Kolkata, West Bengal, 743503

Sir,
Myself chandan maity. Ph.[protected], [protected]@gmail.com.

I wen to mi service center to repair my 3s prime.
Problems was wi-fi & blue tooth not working & every other things was all right. They have accepted service for software problems, but when returned, it was dead condition and asking for motherboard change of rs.3656.
Who is responsible for phone dead? Why they are charging? Where they have to return my phone as working condition.
Motherboard has been locked either their inefficiency or for additional charge.
I want my phone as previous condition. It is totally cheating by service center
Details has been attached.

Requesting please look into the matter, so that we can get justice.
Expecting we will be success to build corruption free india.

Chandan maity