Nearly every government handles things like sales taxes quarterly. Each quarter the merchant submits a report to the government showing the sales and the tax collected in the previous quarter and sends that collected tax to the government.

The due date for submitting the previous quarter’s taxes will generally be late enough that the merchant can wait until most items or services sold at the end of the previous quarter have been delivered or performed.

If you have to refund a customer after you have submitted your taxes you can take the amount of tax that was included in the refund as a credit the next time you file with with the government.