Sony Ericsson — Regardless of regular problem,not at all replacing the handset

I purchased a Sony Ericsson C510 on 30/4/2009 from Planet M, Laxmi Nagar, New Delhi.Since then my mobile had keypad problem.I got it repaired 7 times.Inspite being in warranty I was charged Rs.946 for which I was Served with no legal written
evidence.I urged for the bill, but Service center(Vaishnavi Services, Laxmi nagar.New Delhi)officials denied
for it.I urge for compensation for my money`s worth from consumer forum.Hoping for justice.