pooe loan management

This is not my first complain, I made payment arrangement with the bank and I was told that there will be no interest added on to my loan. the only interest we aggreed on was R 18000. that I was told that I am going to pay towards it. my reference number was starting with unilaw that apeared on my statement. I was pay R400 everymonth,late I received a call requesting if I can increase it I sad fairenough I can add R100 I was asked if I am still using the same bank account I sad yes. the next debit order indicated FNBLAW. the bank did'nt honer what they promised to do changed the ref number without telling me, added interest without telling me. I requested the phone recordings they never gave me. my loan balance is suposed to be closed to finish. I REALY don't know what to do now. I am too small to go against the bank, the make their rulings and we must follow otherwise you will be blacklisted as I am now, my life is now against wall. the bank protects it employees at my expence