Loyal FNB customer but extremely disappointed at FNB's home loan interest rate

We have been banking with FNB for many years. We app**** for a bond 4 years ago and FNB rejected us and we were approved by Standard bank. A year later we decided to apply for a better rate at FNB and Nedbank and we got 10.25% at Nedbank and FNB gave us 10.5% but we accepted FNB's offer so that all our accounts can be in one bank. Now we app**** for further loan on our bond which has been approved but FNB gave increased the interest rate to 11.5%. We then tried to negotiate the rate to 10.5% at least and this morning we got a letter that the rate went from 11.5% to 11.35 percent. Now we have to go to other banks and apply and I am sure we will get a better rate somewhere else. I regret the day i moved my account to FNB because they do not care about their clients. This is a ripoff period and i am very upset. Our debt is less now but we get high interest because FNB thinks people are desperate when they apply for loans. I am highly disappointing and now we have to go through the trouble of applying at other banks because our own bank is ripping us off. Who can help us with this because we will not accept that interest rate?