FNB captures incorrect information - 15 years going

My Statements for my cheque account are still being sent using my ****en surname, hartman. Even though I changes my surname to Bakker over 15 years ago! Fica'd two or three times as well. All my other fnb loan/creditcard etc is under my current surname... how is this possible? Secure chat is non-responsive... I've sent correspondence on the banking app. Why can this not be sorted out easily?