@Jessica149 No, unfortunately you made a mistake that compounded the guest's mistake. When you hit Accept, it locked in the price that was displayed in THE booking form.
What you can do now is go to Your Reservations > Change Booking, and submit a request to account for the correct guest count and price. But if the guest ignores or declines this request, the booking remains as is unless one of you cancels it.
If this happens again in the future, decline the request and then send a Special Offer with the correct parameters. That way, you don't have your calendar blocked up with an incorrect reservation that might not hold when the guest knows the full price.