Soumya i'm sorry to hear that you've had a bad experience with IPL hair removal treatment. If you have had 6 sessions you should of picked up after around the 3rd session that something was a miss with the treatment?
It is typical that you get more hair growth after a session, the dormant hair follicles are activated and start to grow, this is why you have a session of treatments to get different follicles in the different stages.
Maybe the clinic you mentioned (i don't want to get into clinic names) didn't explain to process clear enough for your to understand? But don't let this experience put you off having other ipl hair removal treatments in the future, it's a good treatment that works, maybe try a clinic or salon that offers a treatment with newer technology.
I was reading a good article which is more aimed at clinics and salons who deliver the treatments but it's quite informative on what some of these clinics are doing (link removed)
I hope this helps