Personal information not secure with FNB

I’ve been an FNB customer for over 10 years now & recently they have really been slacking with a terrible don’t care attitude. I’ve been getting sms’s regarding other peoples accounts to my number. I’ve enquired about it with the call centre, on the app with the chat help service & I even went in to the branch where the consultant told me they don’t know how to help I must just phone the call centre again. The call centre assured me that my details have been removed from those other accounts but I still receive messages & this has been happening for months. My concern is if FNB a huge bank can be so negligent with my cellphone number on other peoples accounts, in future what else will they be negligent with.. therefore be rest assured I’ve already opened up an account with a different bank & are on the road to closing my account as I am very disappointed & was always a promoter for FNB which I will now be warning people about before they can think about having an account with them!