Interest rate changed without notification

As a private banking client, i am not happy with the service from Standard Bank. I emailed the Centurion private banking suite for a copy of my overdraft contract as my interest rate on my overdraft was changed without any notification. On the 29th February 2016, I received an email advising that I should wait 5 business days for the copy of the contract. On the 2nd February 2015, I sent a further email advising of the urgency. A response was received stating that resolution date will be the 5th February 2016. Today is the 8th February 2016, and still no feedback given. I had to call the Centurion Private banking suite again for feedback. I have also requested information pertaining to the last increase date of the overdraft as well as the latest overdraft contract. No response received. I must admit, having been a Standard Bank client for the last 18 years, I am inclined to close this account. Ultimately, its about the service we receive.