Where the child is placed with the adopting parents for a probationary period during
            which the child may be returned at the option of either party, the surrender is not
            complete and absolute until the period expires, unless both parties agree to make
            the contract final before the period ends.
         
         After the probationary period ends, if the agency took no action to recover the child
            and the adopting parents kept the child, we may deem the surrender complete and absolute
            unless the agency continued to exercise control and supervision over the child.