Just because you deposit a check, that does not mean the money is instantly available to you. It can take a week or more for a check to clear, and until then, the bank cannot put that money in your account.

Our bank has two lines on the slip you get from the ATM: Available Balance and Ledger Balance. The Ledger Balance includes checks you have deposited, but that have not yet cleared. See if your bank will do this, and if they can give you a list of the last week's transactions.