Provident fund!!

We were contacted by someone from momentum telling us that my father has to claim for his provident fund money in 2016, they emailed me all the documents he needed to sign then we send them back. But they were mute from there, so i decided to follow up with them but they kept on taking me from pillar to post up until one lady told me that I am busy calling and annoying them and my fathers money was only R600, therefore i told her that is it still fine if its R600 they should still send it and she said they will but even today he never received anything. my worry is how can they make him sign papers the they say but the amount was only R600 anyway! Now that he is deceased i really need to find out what really happened to my fathers money!!