Cancelling my Insurance Policy

Hello, my name is Jeffery, a Master student in the Netherlands, originally from Belgium.

Due to the current Corona measures I unfortunately will no longer be working and as a result am no longer insured by the Wlz stipulation, and would have to cancel my health insurance as I am not Dutch. I have already tried doing so using the Zilveren Kruis website, however when asked to choose a reason in a drop-down list, none of the options show up and I can not continue to fill out the form. I have tried this on multiple browsers and experience the same issue. I am under some time pressure as I believe I would have to cancel my existing health insurance policy before the end of December this year.

Is there any way for me to cancel my insurance? Any help would be much appreciated.