Maruti Suzuki — AC filter factory fault

Hi, I am an owner of Swift and on my first servicing i was educated by your technical member that my AC filter is not fitted it is a factory fault so i have to get it fitted at a cost which they charged Rs.450/-. As said i agreed and it got fitted. So my question is, is it true or I am bluffed. And if so why not maruti is bearing the charge for the fault? I went to Spectra Motors Malad Mumbai Service centre Thank you