Denial Of Boarding

I am Dr.Saumen Basu,Consultant Radiation Oncologist,basically from Howrah,now working at Khwaja Yunus Ali Medical College & Hospital,Bangladesh.I was scheduled to fly to Dhaka on Jet Airways flight today morning along with my wife ( Mrs.Arpita Basu ) & son ( Mast.Arkaprabha Basu ).We had valid e tickets & reached Kolkata airport on time but I was denied to board the flight.According to Jet authority the flight is already full.They have given me the reason that it is now government’s rule that 5% overbooking is done in every airline & if I have a valid ticket also they can deny me of boarding flight.
As I am a doctor,I have my commitments to my patients.Is this a rule in our country ???