Keeps on charging collection fees and interest for their mistake

I purchased a couch from Coricraft on the RCS 6months interest free agreement. My banking details were captured incorrectly, hence the debit orders never went off. After contacting them twice to update it and giving through the correct banking details, this still reoccurred. Every month they keep on charging me interest and collection fees for their mistake. Every month I have to spend more 30 - 45 minutes to explain the same story over and over again, yet they still have not corrected my banking details. The incompetence is appalling and there is no respect for their customers time. This weekend I had to repeat the same process and a team leader was supposed to call me back to find a solution, however they never called. I would never EVER in my life do business with RCS again. I'm shocked that any business would want to associate themselves with this careless company.