Misled by standard bank and attorneys

I am a first time home purchaser. I purchased a flat last year July 2014. My home loan application was approved by Standard Bank with an interest rate of 11% at the time. On the day I had signed the contract by the attorneys I was told that after 6 months I could request Standard Bank to reduce the interest rate to the current rate which I have now done. Feedback from Standard Bank is the contract I signed was at 11% and therefore it cannot be changed. (This was read to me this morning by a staff member of Std Bank) What do I do in this instance? I signed the contract taking the word of the parties assisting me and yet when I in turn request the reduction in interest rate as from Standard Bank I am refused assistance. I pay timeously each month &amp