Cell c stole my money

Cell stole my money. I bought airtime for R18 using my Capitec app After deducting R8.20 for an advance I owed I should have been left with R9.80 so I had seen a data bundle I wanted to buy but short so I took another advance of R2 making my total available R11.20.When I tried to buy the bundle it says I'm still short when I check my balance it shows I only have R3.10.Can someone at cell explain why they stole my money.I didn't have my data on has I was using a wi-fi connection so where did R8.10 go. Cell c stop *****ing poor hard working South Africans money.It is the little we have