Nokia 1202c Black [protected] — Poor service

Sir,
My nephew named Mr. Srinivasan has bought Nokia cellphone 1202c Black [protected] on 02/05/09 from UniverCell and he presented it to me. My cell has been hanged and I gave it for service with warranty slip to UniverCell about 15 days ago and they told that cell has been repaired and asked extracharge of Rs.300 for that. When I paid the amount and collected the phone, it was again having the same problem of hanging. When I went and asked them, they told that they gave the phone for service to Nokia at No. 281, T.T.K. Road, Alwarpet, Chennai 18 with bill no. 18819 and now informing that the phone cannot be serviced anymore, either with warranty or even paid and returned the amount of Rs. 300. Please do the needful and inform me what I have to do further?.