Major design flaw to allow the primary device to block itself.
As long as you have the admin password for your router and a computer that's connected to the wifi network, you can unblock your phone by going to routerlogin.net from your browser. Log in with your admin username and PW and go to "Attached devices" and click the link on the top right that says "Access Control".
From there you can unblock your iphone. (set to "allow")
