Standard Bank failing their Clients

I have been a loyal Standard Bank client for more than 20 years. There was a time where I would even recommend them to friends and family. Something has seriously gone wrong at Standard Bank. I recently asked them for an increase in my overdraft limit. Went through the whole vetting process only for them to come back to me stating they can offer me 8% MORE interest on what I have currently had and do I accept this??? They are willing to relook at this if I take more "Products" with them... The same service I currently have but I need to pay 8% interest more than I have now. As any normal thinking person, I said no, but Standard Bank decided to go ahead with this increase regardless without even a letter or notification or ANYTHING. Basically changing a contractual agreement without having a signature or even a verbal or email confirmation from the client. Get this, this is not the first time, they have done such a thing before. A few years back they changed the repayment terms on a place (we have purchased 3 years before) me, my wife and my brother bought for my father from 20 years to 7 without so much as a letter or email or notification to the person paying the bond (me) that the repayment amount has changed, thereby giving me bad credit at the time (and I was buying a house at the time causing me to be declined at various bank including Standard Bank...). Till this day I have not even received an apology from "My" bank... I struggle to think why these big banks can make so much money while providing such bad service and it appears they just take it...