Hello.
After five years of living abroad, in the UK to be precise, I came back to Slovenia and wanted to get insured here again. I have been told countless times by ZZZS that if I want to re-register for Slovenian health insurance, I must first deregister from the health insurance abroad. But in the UK, where I was staying, there is no such thing as opting out, because their health insurance system is different from Slovenia's.  It was only after my own "fall out" with the ZZZS to the effect that "enough is enough for now and I want my insurance sorted out" that they sorted my insurance out.  My case shows the complete lack of regulation (or even ignorance) in this area at ZZZS, especially when it comes to the UK case.