Twin requirements under Maceda Law

With all due respect to this law, R.A. 6552, it could've scribbled clearer phraseology.
Fortunately, the Supreme Court has ruled on cases which make things clearer.
In a nutshell, there are twin mandatory requirements that a seller must do in case the buyer defaults in installments.
First is a notarial notice of cancellation.
Second, seller must refund the cash surrender calue, in accordance with the forumla stated in the law, which generally, is fifty percent of all the paid installments.