@Ruby144 Did you actually cancel the remainder of your stay? Because if you didn't, the host's calendar remains blocked, so it's impossible for him to rebook the dates. Giving notice on Aug 26 that you are leaving 6 days later isn't much lead time for a host whose calendar for Sept. has been blocked by your booking for at least 3 months.
Although if the host led you to believe something other than what he is actually doing, that's certainly unprofessional and unethical.