Useless service from Cell C accounts departmentt

I have had a contract with Cell C for over 19 years, and had my ups and downs with the company but generally have got things sorted out. I recently changed my bank account details, I contacted the call centre and the lady changed the details then said itcwas not accepting them and she put me through to another department who had no clue as to what I was saying. She then told me to e mail Vetting care at Cell C which I did advising of my new banking details this was the 4th of February 25.. I received a response mail on the 10th of February 25with a Vetting case number ***, saying someone will contact me in 24/ 48hours. Todate I have heard nothing and a debit went of my old account which I am due to close. I sent another mail on the 1st of March 25 and still no response. I need to close my old account as I am a pensioner and cannot afford the fees anymore and this company is holding me up the longer it is left open I am paying fees along with the new account I'm moving to.