Disgusting service

I have a discovery credit card and tried to pay an account online. Unfortunately I was not linked to online secure so I called Discovery and an amazing lady helped me set it up. I was then transferred to FNB. FNB asked me to log onto their site with my new details I had just added (including current cellphone number). I did this and an OTP was sent to a number I have not used in 11 years! FNB transeferred me almost 8 times trying to change the number. . Eventually I asked to speak to a manager as the only was they could change the old number was if I knew it (how would I remember number from 11 years ago?!) FNB insisted they got the number from Discovery (how if Discovery have my current number and send smses to my current number) <br> <br> I had an account with FNB until I was 18 years old, I closed my account as I kept requesting a student account and the branch kept misplacing the documentation (3 times!) How 11 years later do they still have my details with an old number and just assume I still have that number. Even though I just registered with the current number? I can't get to a branch. This needs to be fixed ASAP! 11 years later and still shocking service!