I have traded in a car at a used car dealership. The agreed trade in price for my car was $26, 000 and I purchased a car worth $13, 000. So the residual the dealership paid out to me was $13, 000. The dealership direct debited the money into my bank account two days in a row so I ended up receiving $26, 000 in total. I was contacted by the dealership a few weeks later saying that I have to repay the money or I would face legal action because I have received money I was not entitled to. My question: are they entitled to sue me under Australian Consumer Law to get the money back, or is it just a mistake they have to deal with? Am I liable to pay the money back if I know I have received it in by mistake, even if the mistake was theirs?