Legal action threat though full payment is made by tikona

You could always approach the Grievance Department. However, on a personal note, I can advise you that would be of little benefit. The obvious next approach would be to file a complaint with the Consumer Forum, however, to be safe, you can check it in your terms and conditions of the agreement to make sure that there was no such clause to pay such cancellation fee or whether there was any other inconsistency with regard to the charges you were made to pay and the agreement you signed.

Did you get final printed and correct bill before due date of payment?

Get final original bill, copy of SEF, and T&C on termination of connection.

Relate with guidelines and rules available at TRAI website.

If M/s Tikona has collected in excess and have not provided uninstructed service and/or have charged for service that was not provided loge complaint with copy to TRAI and if required pull them to DCDRF.