change ownership of car

Location/place: newbarrackpur,kol-131

Name of company/service: mukesh hundai,vip rd,kol.

Sir,my father purchased a old maruti wagnor no.WB02P2907 from mukesh hundai krishnapur,vip road kolkata on 23.03.2012.It is 4months passed ownership of car did not change still today.Mukesh hundai used car department has been taken Rs.8500 and they ensured him to change the ownership with in 3 months and it will serve by post.My edged father ask them sevarel time after complet 3 months time.It sorry to say that they alwys bypass my fathers request and telling him it is under processing.Please sir, look after the matter carefully.Thank you