Charging to much interest

Initial part of my bond was for the stand, two years later we build and additional amount was linked to the bond at a lower interest rate. Firstly they didn't want to lower my interest rate linked to the stand portion as I was promised.<br> So we put n lump sum amounts over the years so the first part can be paid up faster.<br> Got my statement now with, the first part of my bond at the higher interest rate has not gone down . It should be paid up, but they keep on linking higher interest rate to that amount.<br> I phoned, I they said you can only do that when bond is paid up, they have no answer for me as they cant see on there system.<br> Ridiculous! They are doing what they want as it pleases them, so they can get the most money out of you!