Lenovo — Mishandling with Laptop in Service center

Hello,
I have purchased Lenovo y500 laptop from jalandhar.During my study when i was in pune, i came across with a problem in this laptop.i went to the service center of lenovo whicj is at "Monarch IT Planet Law college Road Pune.".they told me that they will repair it in 3 days.after 3 days they didint respond me and delayed the issue..after 10 days when i went to see my laptop, i was surprised to see that there was a big crack on the laptop and they told me that this is very usual ..whenever you open a lenovo laptop for repair then this crack will always occur..i purchased this laptop for 51000 and now its resale value is 6000 rs only..and the problem 4 which i have given this laptop for repair is still there..