Horrible service ever

Bought a vehicle red BMW 2 series at we buy cars day one it got stuck when we were test driving, the sales person was driving. Following day they called me saying the issue was resolved. After I left their Midstream branch I told them I still have the same issue of drive train. I was told I should bring it on Monday. The car was at their work shop but still it was not fixed. I returned the car and told them I'm no longer interested as I was moved from pillar to post. All this happened 7 day's ago. Today the is a debit for the same car that I returned to them. Why do they debit me if I returned the car.From the day of the car return I have been calling to terminate my contract and I was told it is done. But to my surprise today it is not.