No provision in a mortgage or instrument of indebtedness which denies the rights conferred by sections 2 and 3 of this act, or which provides for prepayment fees in excess of those permitted by this act, or in which the rights conferred by sections 2 and 3 of this act are modified to the detriment of the mortgagor, or are waived or surrendered, shall be enforceable.
N.J.S. § 46:10B-4