Ninety One Reports "Strange" Investment Growth and Ridiculous Capital Gains Tax

My Commodities Fund seemed to be doing really well. So well, in fact, that I deposited more money into the fund. However, it soon became clear to me that the way Ninety One reports investment growth is ***** at best. The "growth" seems to change (in the wrong direction) based on time scale: if you use a small time scale, the growth is large and if you use a longer time scale the growth is tiny. I emailed all the screenshots to them for an explanation. On top of it when I tried to remove the additional amount I transferred (within a month of realizing) Ninety One then indicates a significant value of Capital Gains Tax to be subtracted! Trying to get some sort of assistance has also proven impossible and it is extremely frustrating dealing with them.