Nokia - Too much delay in repairing mobile part

I had given my Nokia * plus mobile to Nokia service center.
Name : Saachi Services
Address:No ****, *st Floor, **th Main, Jayanagar *th Block, Bangalore - ******
City:Bangalore.

there is small problem in charging the phone and They told they take *-* days maximum to repair.
Now its already more than ** days and they did not even start repairing.
When I call them they did not pickup the call.
when I chat to Nokia customer support. They are telling wait for some time around more **-** days more and even they are telling they are not sure whether My mobile will get repair or not.
They constantly telling that part is not available.
They are provide worst service also.