In the event that your standard cash-up report does not balance, it is necessary to perform a detailed cash-up report to isolate the problem.
A detailed cash-up report lists each client one at a time for the day and displays what services they came for, what retail products they bought, and whether they purchased any gift cards. It also lists who sold each item, how they paid, and how much they paid. This will allow you to see if a particular client payment was missed, or was forgotten to be cancelled.
To do this, click on 'My Business' and then on 'Reports':
For 'Report Type', choose 'Cash-up Report' and then choose 'Detailed Breakdown' for the report sub type. Cash-up reports can only be run for a specific date, so you are not able to specify a date range. You are able to view the report 'On Screen', or download it as a PDF or Excel file:
The report will list each client for the day below each other and display what they came for, who they saw, their totals for the day, and how the paid. You can then go through each total, and amount paid to find where anything that doesn't balance.