Product: Checking or savings account

My wife and I recently made a trip to XXXX XXXX, and notified our financial institutions we would be traveling and where. I generally do not use a debit card in situations where I am concerned about financial loss, but I did use my debit card to pull cash from an ATM while we were there.  Unfortunately, at some point during that day, I somehow managed to lose my debit card during this process.  Unknown to me at the time, my debit card was used at a hotel near where we were staying five different times by a group of people who had found the card.  Each transactions was $900, for a total of $XXXX.  Just as we were about to make our travel back to the states, I logged onto NFCU's app to check on a small deposit I was expecting and discovered the charges.  I immediately contacted NFCU to make a fraud claim, and initially, was happy as they credited my account for the amount the amount of the transactions.Within a few hours, NFCU sent a follow up message stating that they had completed a thorough investigation and no error had occurred, and they would be removing the credit.  I contacted NFCU again, and asked how they could make that determination.  They were vague, but essentially stated that a problem with the dates combined with the fact I told them we would be in XXXX XXXX led them to determine that no fraud had occurred.  When I made my initial report, the dates I gave them were the dates on their website (XX/XX/XXXX), which was the date the transactions posted.  The actual transactions actually occurred before that (I pulled cash out on the XX/XX/XXXX, I assume the other transactions were that same day).  I guess this provided at least some of the confusion.When I asked to speak to someone, I was told there was no way I can call anyone from that office, but that they can send a message requesting they call me.   They never called.  I did submit a follow up message that was more specific on the dates, and corrected my earlier error, and now awaiting a "second review".I am not an investigator, but I was able to contact the hotel where the transactions occurred.  It turns out six people were using my card (passing it from one to another) to pay for their rooms as well as other activities.  The manager of the hotel came in late to the transaction, and thought the activity suspicious.  He stopped his partner from processing any further transactions, collected the payment documents, and contacted the XXXX XXXX police.  The six people fled, and he then contacted the bank to notify them of the fraud.I have forwarded this information to NFCU, and hope the second review will provide an actual "thorough" investigation into the matter.  It seems as though 5 repetitive transactions made within a short period of time should have been enough to set off some kind of alarm that maybe there was something suspicious going on, but that did not happen.  Additionally, NFCU made no effort to investigate anything and simply denied the claim within about 6-8 hours.  No follow up questions, no attempt to clarify, just simple outright denial.  A review of some of the other complaints on this site seem to indicate a similar pattern of operations.