All is well that ends well.
When I booked a hairdresser, according to the App, I was going to be taken care of by Marcus. An hour before my appointment I got a message from Glamsquad saying that Renee would be taking care of me. About half an hour before my appointment I received a call from Macy, letting me know that Olivia would be coming (not Renee), and that she would be 15 minutes late. Unfortunately I have at the Botanical Garden, my hotel is in Manhattan and a van is leaving the hotel punctually with all of the guests, so no, 15 minutes late was not OK. I told Macy that Glamsquad should be reliable and arrive ten minutes early, and not 15 minutes late. She answered "but your appointment is at 2:30pm", so obviously she wasn't the right person to speak to. Soon afterwards someone who was great called and said that the hairdresser was in fact on the way and would be punctual. Olivia arrived punctually and she was excellent! Thank you Glamsquad but it would have been better with less drama.