Personal contact info not being updated

Everytime an agent at African Bank phone's me I need to update my contact details with them. Then week after week they keep calling on the telephone number I ask them to remove from my account. Today I received another call on the wrong no. And she couldn't even confirm my updated cell number.

I also keep sending emails to their Insurance email address with update them with my employment details, and yet again I'm told they need to check on that What's the point of updating them? Where does this personal information go?