Blackberry — Handset Issue with my model and delay in servicing

This is with regards to the Handset i brought on 1st january 2012.
I brought model 9300 in white color with PIn no. 2787D68C.
The problem is that i have got my handset replaced or repaired 3 times and every time there is a problem they keep my handset for atleast 15 days.
Last i submitted my handset at Lajpat Nagar center on the 27th september 2012. Till now whenever i call them they say that handset have not been dispatched from god knows where and every time they say that call after 2 days.
I have also written a mail to some rohit who is working with the redington organisation.
I really don't how can they have new handsets in the market readily available whereas they keep the customers complaint pending for months and months. I am really pissed off with the services provided by them. Kindly help me...