related credit card

I took a credit card in 2007 with the limit of 42000/- and based on that credit card repayment the bank offered me a personel loan of 1 lakh ( I didn't provide any document for that). at least 6-7 moths I payed EMI for that loan. after that I stopped paying EMI and I used all the credit limit in card. Last repayment made on august 2009 after that i didn't payed anything. I went to abroad and just came back in jan 2014 and I started new business here i took land line for my office and post paid sim card last week i got a call from debt collectors and they asking my name and date of birth for confirmation and I just said them you called me wrong person. after that they didn't called me.Honestly I just started small business and based on current sitiation don't have enough money to repay them on that time (2007) i dont have enough knowledge about this credit card and all more over the bank rep helped me to get those credit cards by creating some documents. now am getting afraid after those calls its been 7 years since my last payment is there any statute of limitation for debt please help me ...