Harrassment from Kotak Bank

I took an personnel loan from CitiFinancial in 2004 and repaid all EMI's as I remember there were only 3-4 EMI's (around 5K in total) which can be verified and confirmed with my old bank statement. Now, Kotak Bank is approaching saying CitiFinancial overdues transferred to them in 2014, Now Kotak bank employees they started calling and threatening and asking to clear the entire dues and until now i didnt receive any notice or official communication from CitiFinancial nor from Kotak but only via phone calls and emails despite of requesting them to provide me with my Agreement copies and statement. Now, my family member he received an call from an person who represented himself as a court person from Delhi who informs that Non Bailable Warrant is issued in the name of customer, and he said bail cant be requested until 5 days upon arrest, you can contact the Bank advocate to discuss further and provided his number. And my family member called over this number and he informs to visit an Branch office of Kotak in home town to clear the dues and furnish the proof to withdraw from court. Is it true? can bank file a lawsuit in court without issuing an legal notice to customer and If a lawsuit had been filed in the court the court will issue the summon to come and defend personally or issue a Non Bailable Warrant immediately.