Casual leave alongwith headquarter permission.

I left my headquarter giving 4 days casual leave including one sunday in between. Two days before my rejoining HQ, I felt sick and went under treatment. I emailed the sick-certificate to my immediate boss(to whom i had given application and he had allowed me to leave verbally) and the higher officer. The higher officer is replying:- "I had not sanctioned the leave. You left the HQ unauthorised. Action shall be taken acccordingly." Casual leave granting authority is with immediate boss as well. What is the remedy for me?