I hope it goes well for you, support was totally useless to me. The guest I had was completely uncooperative after explaining several times he got an unfair price through some glitch. He may even have figured out some way to game the system, I don't know. Anyway, I discovered that If they booked through instant booking, you CAN decline and cancel it without any penalty. When you cancel, choose the option "I'm not comfortable with this guest". After weeks of back and forth, I finally tried that and it was resolved within minutes. You are allowed a certain number of cancellations without penalty. I had never cancelled in the past. They'll probably get a full refund but at least it opens up your place for a booking at a fair rate.
Not knowing, and never told, how this "low demand promotion" got set up, I've opted out of the first responder program and also removed weekly and monthly discounts, just in case those triggered something. With travel restrictions to Hawaii, and short term rentals not allowed on Maui, we're at a point where we need to offer our place up to locals for month to month rental but I'm apprehensive to set up anything out of the ordinary. Would be nice to at least cover some of our monthly expenses somehow.