Everyone who resides legally and works on Bonaire, St. Eustatius or Saba is insured for healthcare on these islands. All insured persons are included in the insured database of the Health Insurance Office (ZVK).
The care providers can check in this administration to see if you are insured. If that is indeed the case, a care provider does not charge the expenses to you but to the ZVK.
It is possible that you are not listed in the insured database but that you do have a right to the healthcare insurance. Have you not yet registered? Take a look at the registration procedure here. Are you unsure as to whether you are included in the insured database? Please contact the ZVK.