Charles Spurgeon Commentary Matthew 18:16-17

"But if he hear [thee] not, take with thee one or two more, that at the mouth of two witnesses or three every word may be established. And if he refuse to hear them, tell it unto the church: and if he refuse to hear the church also, let him be unto thee as the Gentile and the publican." — Matthew 18:16-17 (ASV)

Leave his company—he has despised the final judgment. Now you must leave him. Do not be angry with him. Freely forgive him, but leave him.