Eastern Orthodox apologist Craig Truglia has two excellent videos refuting Fr. Christiaan Kappes on the Immaculate Conception (William Albrecht and other RC apologists have been citing his research to defend the belief it is a genuine apostolic tradition):
Errors in Fr Kappes’ Immaculate Conception: Part 1
Errors in Fr Kappes’ Immaculate Conception: Part 2
Errors in Fr Kappes’ Immaculate Conception: Part 1
Errors in Fr Kappes’ Immaculate Conception: Part 2
For more on the overwhelming patristic evidence against the Immaculate Conception being a tradition that goes back to the Apostles, see: