Insurance terminated by mail.

Insurance terminated by mail.
Already 62 years Dutch and insured there, I get the e-mail that I must submit a statement from the SVB that I am rightly insured in the Netherlands (not read ..). A few weeks later I receive the email that my health insurance policy has been terminated .. call the SVB, no here is another statement that you may be insured in the Netherlands .. So ONVZ terminated without checking anything an insurance policy by mail (!!) .. Very coincidentally my eye fell on that mail .. Called, mistake no time now .. later .. will be repaired today .. 3 (!!!) days later called again .. who have you been on the line. but it is indeed strange .. they promise me that they will deal with it tomorrow .. and then you have an answer within a few weeks .. Not accepted .. error of you, want it to be repaired now and I am insured again .. and after much penetration I was told that I would be called back today .. I am curious. But anyway .. an email that you no longer have health insurance .. how do they do that when I'm 80 ..