(1) Waiver and estoppel shall apply only to the obligee when there is no order already established by a tribunal if the obligee freely and voluntarily waives support specifically and in writing.
(2) Waiver and estoppel may not be applied against any third party or public entity that may provide support for the child.
(3) An obligor, or alleged biological father in a paternity action, may not rely on statements made by the obligee concerning child support unless the statements are reduced to writing and signed by both parties.