Unhappy with Service from Beamie

We are experiencing problems with Beamie, we are trying to cancel payments for over a year now since we do not own the particular vehicle (FJ Cruiser) that we previously owned but sold. They keep on sending us threatening letters of handover even though we have been in contact with them trying to resolve the matter. We even stopped the debit order. Numerous emails have been sent and phone calls made to no avail. The last person we spoke to, Simon, promised to get back to us last week but this never happened. They then sent us an email saying we owe them R99. Last week and amount of R500 was deducted off our FNB account we sent them another email requesting explanation but no one got back to us. We would like to know how they managed to deduct such an amount without informing us (we will still take it up with FNB as well) they had no right to do this as they were still supposed to get back to us with an explanation. We have all the emails between ourselves and Beamie. Al we want is clarification on what we have to do to stop this as we do not have the vehicle any longer so how can we pay for something we do not have we were prepared to resolve this issue in a civil manner but now they have taken a different route of which we feel is uncalled for, we feel violated knowing that anyone can take money from our account without any notification whatsoever. (Beamie Account NUMBER: 785201)