**********ly overstating interest and charging interest

I according to my statement I was owing 156.20 and the final installment was supposed to be paid on 1 October. I paid on 30 September the 156.20 days. On 1 October they added service fees and interest. I'm shock how can you add interest and service fees after settling my account. When I check the statement they have adjusted my payment after paying. Now I have to 156.20 again for November. This is ***** and continue riping us off.