Gepf query

I got devorsed a year before i redigned. On checking my benefit at work the amount due to me showed R ********** .19. When i was finaly paid out i received R ********** .00. When i inquired by gepf they told me that the difference is due to my being devorsed. The money my ex wife received a year earlier. Should that amount not have been deducted from the total owing me a year back. I dont understand that the amount shown on the system and the amount i received could be so different