Entry of Rats into the AC ducting Spoiled my otherwise good experience

I purchased this car three years back and generally have been quite satisfied with the quality and service standards. However few days ago started getting very foul smell from AC vents and car was sent to the workshop for servicing. They could not locate the suspected rat and assured that the smell will go away. However the smell is still there after a week and car has been sent back to the workshop again. Same thing happened with my close friend and he also suffered a great deal. Mahindra has to investigate as to the possible sources where a rat can enter the AC ducting and plug that ingress.. Hope some one will do something about this and this time worshop will return my car minus the foul smell.