Treatment held back..

Hello,

I'm on Invisalign, on week 11 out of 20. I got a call from my dentist saying she won't be back until the 20th of March, yet I had a booking for the 5th of March to get checked up and get my last weeks worth of Invisalign, yet now I have to wait an extra 15 days and wear the week 11th tray in for an extra 22 days.

Is there a way to get my money back or do something about it because that is a drastic wait time for someone "to return from their vacation". I wanna finish my treatment yet feel like it's negligent from their side to just go on vacation and tell the customers to wait an extra 2 weeks to get what they paid for