Incorrect Matching contribution due to falsified payroll

Office manager has just voluntarily left her job.  I just completed testing calculations for 2017, and the employer was horrified at what office manager's pay was last year (why he didn't pay attention through the year is a different issue).  If her pay was incorrect, then her safe harbor match was also incorrect.  Assuming that it can be proven that she falsified payroll, can her safe harbor match contribution  be corrected?  The money has already been allocated to her account. 

Thanks in advance!

Yes, it can be corrected.  She's only entitled to what is provided for in the plan based on the plan definition of compensation.