Cancellation of service tax registration

Dear All,

One of my client had got service tax registration in 2012.He is engaged in activity related to recruitment of security guards.Till now he has neither kept any records,bills etc nor filed service tax return.Now he wants to close the business and cancel service tax registration.so what is the procedure to be followed?? Do he required to file all the returns till now (2014) along with interest and penalty ??? What if he has not kept any record????