Nokia — Bad service centere of Nokia Care

I have Nokia N 73- Music edition, which 1.5yrs old. when a call came to me, suddenly my phone got hanged. When switched off and on, it stops at the point where "Nokia" symbol appears and did not proceed further and I even tried by removing by battery, but still the problem is not solve.
So I called Nokia customer care, they asked me to go the nearest Nokia care at
Mobile care,
#808, 7th cross,
Mico layout, BTM II stage,
Bangalore-76.

I gave the phone to them in the same day. On the next day when I called them up at 11.00 a.m. They said that they have installed new OS ver 4.8 and everything works fine and they asked to come and collect. When I went to Nokia care at the evening to collect my phone, they suddenly said that both the speakers are gone and not working. But I gave them a set with good speakers and only problem was hanging. They said that they are not responsible for that and gave me the phone and charged Rs. 440 for installing OS.
Not only they have wrongly handled the device and also broken one of the keys of my keypad and kept it neatly that I would not know.

How come both the speakers can go wrong at the same time and that to due to OS hanging problem. I am not pleased by the Nokia care service, which is done by less experience guy at BTM II stage. If the speakers were problem they should have informed me at the morning when i inquired at the status of the repair. but suddenly they came up with a new problem in the evening.
I called up Nokia contact center and informed about this problem, but they are not ready to take up this case or log a complaint.

Please think before and take all precautions before u give the sets to Nokia Care.