<prompt> Human: Hey Reddit! Not sure if this is the correct place to post this, but here goes. My old job which I left in April 2016 sometime over payed me after I had left. I kept the money in my bank and didnt touch it for about 6 months and I heard nothing from them asking for the money back. Just yesterday I received a letter in the post saying that this is my final reminder and I have to pay the money back by Wednesday, otherwise collections will get involved. I havent received anything in the post about this up until now, however the letter claims that its a follow up letter from June 2016, but Im 100 certain Ive not received anything else about it, as its not something Id ignore. What are my options? Could this affect my credit score? Is this classed as debt? Any help would be appreciated. Thanks! Edit: Ive looked at your responses. Most were helpful. Some were not. Thank you to everyone though. And to make things clear, I am going to pay the money back.  <response>: Why dont you start by giving them a call and telling them you never recieved any other letters. Also the money doesnt seem to be rightfully yours, so it would be fair to give them their money back...Obviously sucks to have to give money back though 