A. Keep detailed records of the tasks assigned, hours worked, and any agreed-upon rates. Cross-reference these records with the billing statements you receive to identify any discrepancies. If you find an error, document it and address it directly with your assistant for clarification.

B. Set up a clear billing process where you agree on rates and payment terms upfront. Consider using invoicing software that allows you to track hours and tasks, making it easier to manage billing and reduce discrepancies.