Dad's missing provident funds from CINPF

My name is Fallon. I am trying to help my mom claim my late dad's provident fund from Consol glass/now ardagh glass packaging, as he worked there couple years ago and was contributing to CINPF. This fund was handled by Akani retirement fund at some point, now Momentum. I've called all three places and each leads to momentum. I then emailed all relavant documents as proof he was contributing to the fund, and even included how much he had accumulated by a certain year. However, its been over 2 weeks with no response from all three. Akani and Ardagh reiterated that CINP Fund is handled by momentum now. I called momentum again, and they saying they can't pick up my dad's details. How is that possible? How can a paying client that passed on have funds just dissappear? How is that possible? What is going on?