Disappearing Money!

I have used this app for a long time now and have noticed amounts suddenly not reflecting or being allocated. Recently, I discovered they owed me R5165 (which was not showing in my goals but did show in my investment). I tried to withdraw this, contacted them many many times, have the longest email thread with screenshots and videos of me trying to withdraw per their instructions - and still, two months later- No money. This morning, the money suddenly vanished form my investment, yet it was not deposited into my account. I do not trust this service as now I do not know how much money of mine disappeared without me knowing. The service providers provide no help either. The app is free but today it costed me R5165.