In this day and age, it is important to ferret out all erroneous charges from your credit card processing statement as soon as possible. This means being diligent in reviewing the statements as they arrive. It is possible to find mistakes, and if you do, give your merchant account representative the courtesy of notifying him/her of your dilemma.
Most account representatives, if they are honest and trustworthy, will be happy to review the statement with you. However, if you encounter difficulties in reaching the representative or he does not respond, it is time to get a new representative.