Enough unhappy customer

So I recently moved in to this complex and Top Charge is in charge of the utilities in the complex. So I went to the app and found that my utilities were +-R389 in total and I initiated the payment process then paid R400 to my surprise when I went back to the app I had another charge of R+-R30 I initiated the payment process again then I thought I was done just as I went back into the app again the is another charge added on my account how annoying is that Please help me make it make sense,how do you say your customer must pay a certain amount then just after they have paid you say they must pay again and again….!!! Am so p*ssed with this app or utility management app it’s so annoying and I feel they are just ****ming people out cause how does such happen