Paid account in FULL before get study material now I owe 1700

I'm so disappointed in your company work ethic. I paid the full amount for my course in 2017. So I didn't owe you anything. However I couldn't finish two of my modules due to personal reasons. Now since the beginning of May you have been calling daily informing me that owe you 1700. The person I spoke to in May said that if I pay the amount I will be able to continue with my course. However I received another call from Delano who confirmed even after paying the 1700 I would have to redo and pay for the course again. Now what is the 1700 for as I settled my account with before even receiving study material. And I paid for 2 modules I did not complete. So I fell I don't owe you anything. So is 1700 for electricity and water.???? This is going to effect my credit score mxm.