you ought not to have issued security cheques . once you have signed the cheques and filled in amounts you have authorised drawee to present the cheques for payment . if your cheque has been returned un paid and legal notice issued deny your liability to make payment in reply to legal notice . contact a local lawyer . if case is filed in kolkata it would be maintanable if registered office of company is in kolkata or if as per your agreement in the vent of any disputes jurisdiction is kolkata