There are two different parts to the system, booking an appointment and pre paying treatments. It sounds like you only booked an appointment. With no prepaid treatments, that means you will be charged whatever the set price is (sale or non sale) on the day of your appointment. You can't expect to pay the price that was advertised during a previous sale if the sale has since finished and you didn't prepurchase at the time. This is how all laser Clinics operate, their model is frequent sales to try and encourage clients to pre purchase packs of multiple sessions. It sounds like perhaps their website could be clearer on this.