Drop the matter
From Create Your Own Story
"Yeah, sure, whatever, just don't do it again" you say.
That was undragon like of you.
You need more power.
The princess you have prisoner could give you leverage over her Kingdom.
If you aren't so confident about this, you took make the foreign merchants that travel to the kingdom pay you a toll.
Alternatively, your goblins can take a nearby village, gaining you more followers.