bad service

Good day

I been email with regards to my loan ref number: SDC00774H, This loan I have it for long and been paying it. it was handed over and did not gain interest because it was handed over and I had an arrangement on it. I been paying for over 6 years and I thought I was finished with it, when I asked for a statement it shows the loan start accumulating interest in the last few years. 1. why is the loan not paid-up 2. why did you start charging me interest on the loan 3. why i don't get help