S. K. ENTERPRISES — Misbehavior and abusive language used by the employee of HTC service centre

My HTC mobile phone handset model number HTC DESIRE 816 with iMEI number [protected] is not working, On 15/04/2015 I went S.K. Enterprises at B-52 Kalka Ji Delhi-110019, this ia authorised service centre for HTC and I told them that my handset is dead, after this they told me that we need do the inspection for the same and that is chargeable with Rs. 225/-. I am agree with the above charges and i deposit my handset with them on 15/04/2015 and they provide me the receipt for the same with the commitment of returning my handset in working condition. But when I called S.K. Enterprises after 7 days that is 23/04/2015 they told me call on 24/04/2015 and after that I called them on daily basis and they refused give my handset back. I also called them today (29/04/2015) but they have the same behaviour and one of there representative is using very abusive language me and misbehaving with me from last 2 days and he also threatening me that we are not going return your handset do whatever you want . And when I call the centralised customer care number of HTC ([protected]) make the complain against S.K. Enterprises, the representative of customer care is not responding properly and not registering my complain. So I need register a complain against them and I also Need my Handset ASAP.