You needed to make sufficient RRSP contribution in 2015 to cover your repayment.
Assuming you did that, it appears you reported incorrectly.

You will need to either submit a T1-Adj. to show the correct amounts, or simply let it ride.
If CRA does not receive an HBP repayments, it proceeds as if you have permanently withdrawn the repayment amount and adds it to your Total Income line 150 where it becomes taxable at your marginal rate.