Drop connection and reconnect if I get a private IP address

I have the Peplink Balance One.

One of my ISPs has more clients than IPv4 addresses, so sometimes they will lease me a private IP address in the 172.16.0.0/20 range instead of a public address.

In my previous router I set a script that would check the IP address after every connection, if it was a private IP, it would drop the connection and connect again, until I public IP was provided.

I need help setting a similar script in Peplink Balance One.