Interest Allowed But Not Principal Amount On Home Loan!

I have taken housing loan in 1999 for Rs. 1.53 lacs and then addition loan of Rs. 3.50 lacs for addition to the same house and constructed first floor. Again I have taken one more housing loan and made slight modification to the same house. I repeat I have three housing loans and all the loans for the same house. Further in the above 3 loans, 2 loans are for construction of additional area for which approved plan is available I wanted to k