Service tax audit by department

Nidhi Rana (Project Controller ) (24 Points)

07 April 2016  
on 7th April'16 we got a call from our CA that we have a service tax audit on 11th April'16 from department but according to my knowledge, department always give 15 days prior notice before coming for audit that is also after giving intimation. They are coming to our registered office that is in Delhi. can somebody please write a correct procedure to be followed by department