Hi,
In your case Money back amount is not taxable.
It is totally Exempt u/s. 10 ( 100 d of I.T. Act 1961), as you are only getting your principle amount back, just like a pre-mature Fd or withdrawal from PPF. You might have also received a Letter from the LIC for Tax purpose, stating that the same is exempt. Please do not forget to declare this amount in Returns as "Tax Free incomes"