HOW CAN MY MOTHER GET HER DUE SHARE OF SP RETIREMENT SHE WAS MARRIED FOR 25 YEARS TO MY DAD AND?

MY MOTHER IS WONDERING WHY SHE IS NOT GETTING ANYTHING FROM SP RETIREMENT, MY FATHER WORKED FOR SP SINCE ABOUT 1963 TO 1983 SHE DIVORECED HIM AFTER 25 YEARS IN 1982. AT THAT TIME HE MADE HER SIGN PAPERS SAYING SHE HAD NO RIGHTS TO HIS MONEY, WELL, WHEN SHE RETIRED AT AGE 62 THE SOCIAL SECURITY OFFICE TOLD HER SHE HAD RIGHTS TO THAT MONEY NO MATTER WHAT HE SAID, SO SHE CALLED THE SP OFFICE AND THEY TOLD HER YOU ARE GOING TO GET ABOUT $600. OR SO DOLLARS. WELL WHEN HER FIRST CHECK CAME THEY ONLY SENT HER $20.00. SHE GOT SO UPSET THAT SHE TOLD THEM TO KEEP THEIR 20 DOLLARS. I FEEL THAT SOMETHING IS WRONG, NOW GET THIS HE MARRIED ANOTHER WOMAN WITH THE EXACT SAME FIRST NAME AND MIDDLE NAME. IF ANYONE CAN DIRECT US AS TO WHERE MY MOTHER CAN GET THIS STRAIGHTNED OUT WE WOULD APPRECIATE IT. sincerely, dn