Sorry to hear the Sapphire spa was experiencing problems. If you're in doubt, you may want to cancel and book on board. The spa runs specials daily, so check out the Princess Patter each evening. One nice special is the week pass for a couple which run $109 (this is for the both of you). You have unlimited use of the hot stone beds, saunas and various showers (mint shower, tropical, shower and one other to choose from). Treatments were extra, but again, check for specials. Oh, for the week pass you need to go the spa the day you board and sign up for this special. Enjoy!
We have not pre-booked our spa services, we book them first day on board. I would keep the pre-booked appointments, just go to the spa on the first day to confirm them. Do you have some sort of documentation that you could bring just in case?