To start with, you need to know that any duplicate payments can cost small startups as much as $ 12000 per month. The main reason for this fee is the incorrect Invoice Number Error. However, there are various reasons for the Invoice Number Error such as typos, spelling mistakes or simple human errors. While rectifying can be a task, however, it can be done.  One of the foremost rules of thumb is that the Invoice should not be deleted despite the reasons. In order to rectify this, it is recommended to create a new invoice altogether along with the correct information. Now, send this invoice to the client in question along with a note of correction in order to avoid any further confusion. Also, most experts recommend avoiding the occurrence of such errors altogether, this can be done by hiring a professional expert or Accounting software that can automate the invoice number creation for you. In case the mistakes continue to occur, with the help of the right kind of software, they can be pinpointed immediately. Not just this, but it also provides the exact location of the error and how to resolve it as well.