I sent my Maruti Zen with my driver for a top-up of the AC gas. This service genrally takes around 150rs in any other Service station. Carnation gave some story convinced my Driver that the entire gas will have to be replaced which would cost around 400rs. After the procedure they showed a bill of 1200rs - 3 times the estimated amount.
I unfortunately was not present to question this rampant cheating. Would everybody never to visit Carnation.