Changing date- freaked out

Just booked a cruise and after clicking the payment of $900 non refundable fee the date switched to the previous date my TA had put on hold. I don’t understand and the cruises were both the same price. Is there like a 24 hour rule to cancel? I emailed right after - she will be in office tomorrow. I’m super stressed and don’t want to pay extra. Thank you for any insight!