Collection charges & I never missed a payment

I've been a Foschini account holder for more than 15 years. Last month I accidentally short paid my account & was charged interest, which I don't mind as the oversight was mine. However, I was also charged collection fees for an email and sms that was sent. When I queried these amounts, Tanya Coetee advised me that collection fees will be charged on my account for any skipped or missed payments. However, I did not skip or miss a payment & I responded saying as much. When it was established that I did not skip or miss a payment, Roefkah Ferreira then responded advising me the charges are in accordance with the Debt Collectors Act. That I will be charged if I short pay or miss an installment. Those are now 2 very different and inconsistent answers. Why am I being treated like a delinquent client who has not paid on my account at all? Other retailers do not initiate the debt collecting process when an installment is short paid. They initiate these when the customer has not paid their installment at all.

It does not sound proper, to charge a client who has made payment on their account interest AND collection charges. That kind of client service is not reasonable at all.