Poor customer service

Iam a very disappointed and unsatisfied with the store Lewis in Denlyn mall Mamelodi, I send my son to pay the installment at this store, he was told by the cashier of that day on the 29/10/21 at 11h14 that the acc is in areas he must pay R800 of which the installment is R650 and I pay R700 every month on July month the areas were -R70 and they called July 30th which I went to pay,from there I got the story of areas everymonth.now I talked with the cashier through the fone for clarity how do I have arrears we're as iam paying more and on the bottom slips it where as no arrears but top right it shows -141,I asked the clarification there she seemed not to understand and told me I should come to the shop which is not my first-time of that type of a question, ,that irritates me a lot,I would like Lewis store furniture in Denlyn mall to have a regular visit by area managers blacks and White's maybe they will be a change of customer service, why I also mention that, is because when I go pay i will wait for more than 20min it doesn't matter to them,u find cashier counting money right there,the staff should be trained to respect money and customers.