Poor competency from Truworths staff

The level of competency i have received from the staff who manage the Truworths accounts has been absolutely shocking. Here is my experience, when i had received my June statement, i was already confused, i had visited a store to return a few items on 2 June and this credit did not appear on the statement they generated on 11 June. I found it very odd, that on the day i had purchased a scarf and this purchase transaction did reflect on the statement, yet a return which was processed 9 days before statement date, did not pull into their statement. Never the less, i wanted to pay off most of the balance owing and calculated this taking into account the credit and made payment. For the past 3 days i have had 6 staff contact me to advise that i am overdue on my account by R95. None of them had the intellect to comprehend what i was saying to them to rectify the situation, which is causing me to be continuously harassed by them. I am so frustrated by this experience that i have decided to no longer purchase from the retailer. The R95 is pocket chain for me but it is the principal of them demanding payment from me, when they are not managing the transactions on client accounts effectively. This is what you get for being a loyal customer, a loss for them, if they pull my history they will see if generously buy and pay off my account quite quickly.