HDFC credit card issue / Dispute with Merchant

I have made a payment to Panorma Magic Holidays in April 2013 through my HDFC bank credit card and they have a tie up with HDFC bank to make the full amount of Rs. 27576/- into 18 months installments. I made the payment for the next 4 months to HDFC bank and suddenly got a call from Panorma Magic Holidays and they refused to provide me the services which was offered to me by thier sales representative and closed my membership. They asked for additional amount of 1,52,000 Rs. for which i refused as it was never committed to me. Due to this issue, I stopped paying the installments to HDFC bank and filed a complaint also with the bank. Apart, i have also filed a complain to AKOSHA team to help me in retrieving my amount from Panorma Magic Holidays through which i got the legal papers 2 days from AKOSHA team to file a consumer case against the company. Today, I got a legal notice from some lawyers on my email on behalf of HDFC bank to present myself in Tees Hazari court and attend the conciliation camp. If I failed to do so, they will initiate legal proceedings against me. Please help / guide me what to do in this case as this is mentally harrasing and disturbing my life a lot and I am a simple God fearing person who got trapped by that Merchant (Panorma Magic Holidays).