As a private banking client, I received the worst service from a bank EVER!

I just got off the phone now after being on hold for 35 mins & got attitude and dismal service from one of FNB's call centre agents called Mlungisi - I wonder if that's even his name because when I asked for "Mlungisi's" surname and told him I would be complaining on Twitter and all social media platforms regarding FNB and his service, he told me "Go ahead" and put the phone down!! I don't even know if my query was resolved or not! FNB's slogan for private banking clients is "Banking with Private Clients means that you will experience a superior level of service and rewards" however after this call this morning, their service is the exact opposite of what they claim it will be for private clients!