If the whole payment is done the Builder should not have any problem in going for registration as you have a housing loan on that property so Bank must be looking for the registration papers and may I ask you if it is delayed.
You don't have the property transferred in your name definitely you cannot get the electricity connection in your name please speak to the Builder to try to get the property registered has he has nothing to pay to the register in case there is a problem in registration then you can move 2 the consumer forum and complaint