Delaying Cancellation to ***** money from poor society!!

I registered with damelin correspondence last year 30 November 2018 and they started to deduct on December 2018,by January 2019 I decided to cancel my studies because of financial circumstances. They promised to cancel my course with in 4 to 5 weeks, but since then they still deduct from my account and I have been reversing my money. Now this situation is affecting my credit status and I am now in arrears. I really need help because when I phone them they keep telling me that they are still in the process.