Service center didn't handed over the phone in working cond.

Dear sir, 
I submitted my handset to SONY authorized service center(will be called ASC hereafter) for screen issue, which the ASC, rejected by showing water ingress in it and thereby giving an estimate of rs 6400. since the phone was never in contact with water as per best of my knowledge, I rejected that estimate and asked them to pack my phone back in original condition as submitted. Now upon taking the handset, it was not properly packed (the back cover was partially opened) and the phone was not detecting the SIM, whereas the phone was in fully working condition (except screen issue) before submitting to ASC.The ASC is not willing to fix this by giving improper reasons like the sim issue is due to software upgrade etc.
Now, my question is against whom should i file case . SONY india pvt ltd, or ASC.
Further, what compensation can i ask from honorable court for this.