The prince of this world is not Satan, but exactly who it says it is a prince of this world. Satan works through this world's princes by means of his minions for he himself was bound by Jesus whilst Jesus was ministering on earth (Matt 12.28-29).Satan is not, and never has been, the prince of this world. He only claimed to be. But he is a liar.
The angel was able to incarcerate Satan because he had already been bound by the authority of Jesus and the Holy Spirit. It occurred during Jesus' ministry (Matt 12.28-29)
It is all quite simple really for those who actually believe Scripture..
That interpretation is actually kind of funny. So it's YOU here that's actually the JW saying an angel incarcerated Satan.