Lack of accountability and transparency

I am a former employee of Soweto City Council Pension Fund, we were later moved to SALT administrators to handle our pension fund. From that migration there’s a portion that was said to be kept until retirement. That money was kept at Old Mutual Corporate administration. We were given certificates stipulating the amount at the time, now my problem is I have since retired and misplaced that certificate. I have visited countless Old Mutual branches and made calls for assistance to claim that money and I am being told I need to produce that certificate but surely they should have it in the records that there are funds which were not completely distributed? I want my money and no one at Old Mutual has assisted me in resolving the matter.