I assume you have communicated with Michael about this? He's really the one you need to talk to. Send him a private message or a personal e-mail. You should have his e-mail address since you've communicated in the past. A WikiTree team member would only want to intervene if he's an aggressive, destructive vandal, and based on his contributions I don't see any indication of that.
WikiTree is a wiki so mistakes can be fixed. I only see a few edits from Michael so whatever mistakes he made won't be that extensive.
I know collaboration can be hard. It's the big challenge of sharing one worldwide tree instead of having "your tree" and "my tree."
For reference, please see the mission of WikiTree http://www.wikitree.com/wiki/About_WikiTree and our Honor Code http://www.wikitree.com/wiki/Special:Honor_Code
For specific help on how to make edits see http://www.wikitree.com/wiki/How_to_use_WikiTree or post a specific question here.
I understand you have limited time, but we do need to collaborate on WikiTree, even though it would often be easier to work by ourselves.