Hi all, Hoping you are able to help me with my predicament. These are the facts: I took out a car loan from Autoco* (One of the finance companies)for $10,000 on 01 June 2013. The period of the loan was 5 years. I sold the car in early January 2014. I phoned Autoco and requested the early payout figure. Autoco responded via email (signed document attached to email), stating that the payment of $9,000 was required to finalise my loan. I sold the car for $11,000, paying $9,000 directly to Autoco and keeping $2000 for myself. I spent the $2000 on a new camera. On the 24th of April 2014, Autoco sent me a letter stating that they miscalculated the payout figure and said that I still owe them $1000. Without this payment, they say they still have encumbrance on the vehicle. On their end, my account was accidentally credited twice (once at the beginning, and once at the end) for an insurance product that I cancelled within the cooling off period. Essentially, my account was mistakenly given $1000 credit. Legally speaking, I'm not confident that I have a legal requirement to pay this sum back. Is there an implied term (based on common business practice), that the by requesting the final amount, and by paying it, the contract has been completed? Under consumer law, is this not 'misleading conduct'? If I disputed this, would they be claiming unfair enrichment? If so, could I not use the defence of 'change of position'? Essentially, I had acted in good faith the complete the contract, and their error will leave me out of pocket. Even though the credited money was not mine, I was not aware of this and spent it in a way that is irrevocable, thus I would have to suffer a detriment to pay it back. Any other tips? Hope this is enough information and thanks in advance for your help! * Not real company name.