I have bought one flat From DS-MAX near Varthur, Bangalore. SBI has sanctioned loan against that pro

I have bought one flat From DS-MAX near Varthur, Bangalore. SBI has sanctioned loan against that property. Just few days before I came to know that builder is not going to give me the Occupancy Certificate (OC). However they will transfer Khata in my name (that too "A" Khata). I asked them why you can't give me OC , have you constructed something illegal? Then they showed me the BBMP approval for the plan. I am confused now if everything is as per BBMP approval then why BBMP is not giving OC ? Also I heard about Akrama Sakrama. As per this scheme, my flat will get OC after paying some betterment charge. Is it true ? How likely is that BBMP will demolish the flat if we dont have OC?