Are you receiving a sickness or unemployment benefit? Or are you receiving a statutory pension, but are you also employed in the Netherlands? Then you are still an employee and remain insured in the Netherlands. You are therefore not entitled to an S1/121 if you emigrate.
Are you receiving a Dutch statutory pension, but do you also receive a pension from your country of residence of do you still work there? Then you are not entitled to a S1/121 (because of prevailing rights). You need to arrange health insurance in your country of residence. Are you not sure about your situation? Please contact us.