Airbnb has agreed that they have a bug in their software resulting in the wrong price to the booking clients as well as the wrong base price for the promotions. It has been a challenge to prove it to Airbnb since they denied it.
Finally, I was able to demonstrate the bug and I have been reimbursed for two bookings by Airbnb. I have been using the PC interface. I am still struggling to get reimbursed for the other bookings that have the wrong price.