You can file the case before the state commission if you interest, compensation, rent is more than 20 lacs and if more than 1 cr then before National commission. There are judgements that you can claim interest at the rate on which builder is demanding interest as per agreement on delayed payment and also claim rent from the date of expected to hand over possession. You may contact me on mail id
lawjuris09@gmail.com. I have recently filed 25 cases. My cell no. 9811054562