Discounted Multiperiod Settlement for Woolworths Store Card Dilemma

In December, I got into an agreement with Nimble to settle my store accounts, the Mr Price one has been settled. For the Woolworths account, I selected a discounted multiperiod settlement for my Woolies account to make 6 number of payments and the repayment amount was R3449.71. However, this balance does not reflect when you send me my balance statement and there is interest I am being charged whereas the agreement did not stipulate any charges. What saddens me is that when I get on their WhatsApp line, they keep saying they will escalate and escalate the matter. I receive no feedback and the matter is still not resolved.

How are we supposed to settle our debts with such incompetence and poor customer service. All I want is my agreement to be adhered to. They do not bother to inform me who is assisting me on the chat because I like to keep a record of these things.

I asked them for a settlement letter for my Mr Price account, till today I have not received it. Yet, they do not forget to debit my account every month.

Is good customer service too much to ask for?