Dell Inspiron 5408 - Defective keyboard

I had recently got Inspiron ** **** model and it dint even took * months for keyboard to stop working properly. Now, every time I need to copy paste certain letters while typing which is a very hectic work as >* letters are not working. I complained dell service center and they agreed to replace the keyboard as it comes under warranty. Its been over * weeks, I was informed it might take another ** days and all of a sudden I get a mail reporting that keyboard will arrive in June/****. If a company is selling so many defective laptops (I'm telling it only after going through customer reviews over dell products), they should take immediate responsibility in replacing default parts.