Everything else Q!

We are in Thailand on tourist visas and in the process of applying for guardian visas (pretty straightforward and our kids are on study visas and enrolled in an international school here).

Issue is, the company I shipped our personal belongings with from Canada is telling me our shipment is subject to duty and I'm expected to pay tens of thousands of THB before they release it? I did not know this and thought personal belongings were not subject to any tax. The shipping company says the only way to avoid this is to obtain a work permit. We did not plan for this...!

Any advice or insight please?!

Thank you!