Voltas Vertis AC review: Front Grill Lock broken 2

I purchased Voltas Vertis 1Ton A/ C on 2nd May 2010 from Croma, Rohini. They came install it on 4th May. They didnot use the ply during installation, instead fixed the thermacol from where the dust drop come in. After installation, we found that the Front Grill Lock was broken. We lodged the complaint at the customer care on 6th May. Since 6th May 2010, we have been calling VOLTAS CUSTOMER CARE every 2 nd day. We are promised by every representative that a technician would visit. Nobody comes though. We have talked to several supervisors, no action has been taken yet.
They guarantee the warranty of 1 year. Its not been even 2 days we found that it was broken from the company... This is the value for our money, ..Waiting for last 20 days. We regret buying a TATA product.

We feel like cheated.

Please suggest how to deal with this.

Parul
[protected]@gmail.com