Recovery process of Personal Loan.

I had taken a personal loan in 2006 from Abn Amro Bank and was repaying regularly.When a total of Rs.5000 was due my business failed .I spoke to the Manager stating my problems and he verbally waived the balance due, although no NOC was issued.But I was not further disturbed. Later Abn Amro sold to RBC and the debts were purchased by an ARC.Now they are calling and asking for repayment of Rs 57000,although they had not initiated any legal process till date.Cheques with the Bank have become obsolete by change in the cheque format. My question is can the bank legally enforce the recovery, as more than 7 years have passed since the 'default' and the Bank has not moved legally.What should I do?