Sony Ericsson W580i — Phone not delivered by service centre from a month before

I purchased 1 pc. Sony Ericsson W580i cell phone (IMEI No. [protected]) from Hotspots retails pvt. ltd. Bhootnath Market, Indira Nagar, Lucknow on 23/12/2007 for Rs. 11950 (Inv No.[protected]. After using it for sometime, the cell has problemed and I complained the same to the authorized service centre of Sony Ericsson (Soni Ericsson Service Centre, Suratdeep Complax, 1st Floor, D-Block, Swantra Bharat Campus, 16, Rana Pratap Marg, Lucknow) on 03/06/2008 and deposited my handset . On 05.06.2008 I got the cell from service centre. But the problem was still and back of the phone was changed. I once again deposit my phone to above centre. I discussed with the concerned Ms. Robina Gujral and she told me that motherboard of the phone problemed so handset will replace the same with the new one as it is under warranty period. Subsequently, I deposited the phone to them. She said that H/S will be delivered on 22/07/2006, Thereafter I paid several visits to them followed by phone calls but they are not giving any head. It is almost 15 days have passed.
I am a common consumer and facing a tremendous hardship due to such practice of the authorized service centre. I seek your kind intervention to get me the replacement and the compensation for the delay and the strict action against the authorized service centre, M/S Soni Ericsson Service Centre (particularly the concerned officer Ms. Robina Gujral) so as to curb such unjustified and unreasonable acts of the manufacturers and service providers.

Consequences : I am without phone. Since I cannot afford to buy a further new handset.