Bad Billing - Commission collection goes high

I paid my account last month for R5000,00 on the 26/11/2018 and now when i check the collection commission is R575, but after not paying for so many month the collection fee it was R50 - R100, now that i am planing to close my account the billing is getting more, it does not make sense, worse part its difficult to get hold of you, you always get cut off. this is pathetic, how did you get to R575,00 and the commission was allocated on my account on the very same day i made payment. this is sick i need a proper explanation, even the prices they do not go up like this.