Failed to change cell phone number

Very poor service received from standard bank vehicle and assets. Since last year I have been trying to update my cellphone number with them but they are failing me many times. Each time I speak with thier agent and managers they always confirm it has been updated but they always send my private information to strangers. I'm very disappointed. What a big company it is but fail only to change cell phone number. I have been promised so many times that my information have been updated but I don't receive any communication from then but I had to hear from other people about my private information from standard bank. I really regret now having this relationship with you.