Homeloan interest

I called FNB to enquire about the interest rate I was charged last month on my homeloan , I do not get statements as I do not bank with them .advised to go the branch to get 12 months statements, I got last month statements from my ex-husband, the service agent(Lerato) said she cannot explain why it was high and referred to me to collections department who said they have nothing to do with the interest especially if the account is no longer in arrears I was then transferred back where the voice prompt kept on repeating the same thing even when I had chosen option 1