My husband says he has got polygyny permission, but I was never called to court. How is that possible?

This needs to be checked urgently, because the existing wife is usually called to be heard before a decision is made. There are several possibilities: the notice was sent to another address, the application has not actually been approved, or he married without going through the court. Ask him to show you the permission order. If he refuses, see a syarie lawyer or an officer at the Syariah Court, and bring your identity card and marriage certificate to ask about the next steps. If it turns out there was false information about your address or your consent, this can be brought to the court's attention. Do not stay quiet for fear of causing a fuss. See a wife's rights if there was no permission.