Not sure if you’ve tried it yet, but there’s a self-help option to move the character(s) to a safe place which usually resolves issues like this and you can find it here:
https://us.battle.net/support/en/help/product/wow/197/834/solution
If that doesn’t work, you’ll need to put in a ticket using this link:
https://us.battle.net/support/en/help/contact/1369/ticket