Truworths *********** to fix their mistake on account

I have been receiving SMS's and calls from Truworths for more than two weeks regarding my account. According to them I am in arrears. I have visited the Truworths Mountain Mill Worcester branch 5 times, each time giving them proof of payment which I made 28 January 2025. I have emailed the proof of payment numerous times to the customer services and POP addresses and everytime they "escalate" my proof of payment. But still no effort on their side to rectify their mistake. I have CC'ed the CEO Michael Marks in the emails and yet my account still shows "overdue". I am beyond fed up and frustrated with Truworths and want to close the account which I had since 1999 and have never been in arrears except now due to Truworths's incompetence.