Matthew never collected anymore taxes but spent his life following Jesus, spreading the gospel, and most likely going to the people and places and others would not go like Ethiopia where he died according to writings outside of Scripture. Christian tradition says Matthew died in Ethiopia spreading the gospel into Africa by the sword. 

He died knowing He could of collected taxes for Rome and life of power, position, and wealth. But he gave up that life and lived a life for Jesus by spreading the eternal, life changing, power of the gospel of Jesus Christ. You make sure you do the same. Answer God’s call on your life and live your life for Jesus, only Jesus!