Standard Bank Home loans...********** Service

So what should have been a joyous moment in my life, has turned out to be one of the worst experiences ever.I read Dereshans complaint and realised that I went through the same, the contract i signed said 10.5% but the amount im paying for is not 11.6% the contract states that the retention amounts would be lifted once my house was done, as it was a building loan. my house was already completed , just by the way, I called them numerous times for them to lift the retention monies amounting to 1.5%. 2ndly, i had asked my banker to make my payment period 30 Years as im only 26.he agreed, I dnt know what changed but now im paying my Bond over 20Years, resulting in me paying over R7000...SEVEN THOUSAND RAND pm.I asked them if they cannot rectify such and they have refused, i keep telling them that I cannot afford it and they keep telling me that I can, I have asked if we cannot rectify their error and they say that they cannot. surely contracts can be amended and ive been a loyal customer to them.someone please help...