Top Level Task Marked as Complete

Recently, one of the users of a large Planner project marked the top level task complete and then it appears they marked it not complete.  This appears to have reverted the entire status of every task in the 1000 item project to incomplete with a 0% status.  I see this is the history log, their name is on every task's history now.  Is there any way to revert this or lock out non-base level tasks from having a "complete" selector?