<prompt> Human: I made a 20 down payment when I purchased my home about 3 weeks ago. I went into my credit union to retrieve my bank check the day before closing. Most of the down payment came from my savings account, while a few thousand dollars I brought along with me. I run a eCommerce business and occasionally sell a few things locally.Everything went smoothly and I got the check and went on my way. 3 hours later I get a message from my friend on Facebook saying I need to call her at the Credit Union. She is a trusted friend, who did not complete the deposit or issue the check. So I call her and she stated I had a counterfeit 100 bill and that I need to come pick up the bill, and that they took 100 from my checking account. I could easily see this occurring as I accept cash payments. However I had a problem as they didnt tell me right away during the deposit Maybe this was their policy? I still would have to check on that. But, my concern is why it took that amount of time to tell me it was fake. How do I know it was my bill that turned out to be fake, and that it wasnt mixed in with another customers, given the time frame it took to reach out to me.Another quirk is that the teller ran the counterfeit bill detector pen through each bill and they all turned out fine with that test as I watched the teller non-friend.When I went to go pick up the bill a few weeks later, the original teller who completed the transaction was not in, and my friend could not find where she placed the bill. She attempted to call her and nobody answered I should have stuck around until it was given to me, but I left. The teller has been with the credit union for at least 15 years so she knows how everything works. So I found it odd they couldnt find the bill when I went to retrieve it the first time, and that the original teller was in charge of hanging on to it. She is more along the lines of the person who is in charge of all the tellers. So I go back a few days later and I get the bill. The teller my non friend said it didnt pass through their machine. She recommended I take it to the police. There is zero chance I can figure out which buyer gave it to me from which specific sale, so thats a dead end. Now, I dont even want to even think the teller committed a crime and swapped a fake bill with one of mine, but it feels entirely possible given the circumstances. I am fully fine with this loss, but after talking to a few friends and family, they thought it was odd and said I should raise a concern. Im guessing the credit union has some sort of insurances for this, but I dont want to raise a stink if the bill is actually fake, but the circumstances are just questionable. Just wanted to share this interesting scenario and see if anyone can offer some advice who may work in the banking industry. Should I bother calling and asking some questions? Ive been with this credit union for almost 15 years. Resolution I contacted the credit union, spoke with a higher up and explained the situation. She was very understanding of hearing me out. She called me back about 30 minutes after we spoke and stated they will credit me back the 100. Asked me to return the bill which I did today. She said I was absolutely right that the bill should never have been returned to me and they will use this as a refresher on how to handle situations like this. She was appalled they contacted me via Facebook. Additionally, the higher up explained that specific tellers transactions that morning, and said they believed the counterfeit bill 99 came from my deposit, however it turned out to be a washed out bill. Basically, it was previously a 10 and turned into a 100, which explains why it passed the pen test. Stated again it was the credit unions fault and they will fix this. In the end, I am satisfied! Thank you for all of the responses! Assistant: 3 hours later I get a message from my friend on Facebook saying I need to call her at the Credit Union.Find a new credit union.Human: Even though this was a friend who did NOT process the transaction, who I do absolutely trust!  <response>: They seem disorganized. For all you know they mixed up the bills and that was someone elses 100. They should have money counters at each teller station and use them whenever you deposit more than a handful of bills. 