HDFC Bank — card lost but payment came

Hello!
I am Samir, I have problem with HDFC bank. It all so happened that I received a credit card from this bank in 2006 in 2008 I found that my card was misplacing
so I loged a cmplain for this and the day I found it lost rang-up the customer support and asked to stop my card now.

It has been 5 months since that and I received a legal notice by them stating to pay the amount of Rs 20, 000 within 7 days (I received the notice when already 7 days passed ) else would be dragged to the court for the purchses I didn't ever made. Now these days am getting THREAT calls form the bank 'Threaters/Goondas' that if I don't pay the amount witin 3 days "Hum apke kapre faad kar nikalwa denge" (as per the threat words used)

I am really pissed off by their behaviour...