Account is in arrears - But shouldn't be!

Two months ago I got a phone call from a lady saying that my account is in arrears, and I didn't understand how that is possible, as I have a debit order with Rochester, and have been paying my account every month. I got a video message saying that my account is in arrears. I phoned them to ask what is going on, and they said they will investigate as they can see that my account is up to date. They phoned me back later to say the matter has been resolved and a month later I get the same message saying my account is in arrears again after the debit order has gone off. I phoned again yesterday (19 May 2015) to actually cancel my contract and that they can give me back my money and come and collect the furniture I bought from them. Then they tell me they can arrange that to happen but I must know that the furniture will go on auction and whatever is left of the outstanding amount I will be liable for! I think this is the worst service I have ever received from anyone. I will never buy anything from Rochester again nor will I recommend it to anyone.