Disappointed n confused of the balance once again.

It has done it again in the early hours of 26th November 2024 where I checked my balance and it was R11.20.I tried buying data that i could afford with included vodabucks only for it not to show even now that R250mb never showed.That moment i got message that the R6.10 will be deducted on my next recharge.I checked again why it didnt show that time I had R14.10 which i didnt know where it came from.I tried buying data again worth 250MB and it was successful and for R10 to be deducted from my next recharge.