Credit issue not handled properly

I am really shocked with the service I got from Vodacom subscribers collection department. I am owing Vodacom R2800 and I am close to finishing that account . I made an arrangement with them to debit my account R1200 every month until December 2019 of which I know I'll be done with that account. So I had a hiccup and defaulted in the month of September however on the 20 October 2019 when they debited they received the payment so they then sent me a message on the 28 October 2019 to say I have to call Vodacom cause the arrangement has been broken so I tried calling on the 29th however I couldn't get through so I then thought its okay when they debit they'll be able to debit or I'll do an EFT then on the 04th October 2019 at around 12 pm midday they closed my line. So I called the customer service desk and told them what had happened and I then asked if I'll be able to get my line open and I was told that yes ,however when they put me through to the subscribers collection department I was told that I won't be able to get my line opened I so shocked cause ever since I made the payment arrangement I honoured that arrangement. The sad part is I missed one payment but in October when they debited they received the payment doesn't that count for something? Clearly it shows that like any customer I had a hiccup and of which I wanted to rectify. With my knowledge when you owe any credit accredited company you are communicating with of which they only communicated with me only via sms and they could have called to find out if I could make that payment of which I can even now I feel I was not given a chance to rectify that mistake cause I do have the amount that needs to be paid but still I get told I won't get my number back. Whats worse is I can even eft that amount but I can't cause I use that number for my cellphone banking and its closed . No matter what happens the company was supposed to give me a chance of which they didn't and according to the NCA law the company was supposed to take necessary precautions before they got to the conclusion to just close my line . I will not take this matter light but I will go as far as I can to get my number back.