@Mike-And-Beth0 As Emilia pointed out, that's what your calendar settings are for. Why have your calendar open for the indefinite future if you can't accept those bookings?
And there are ways to avoid having to decline inappropriate requests by asking the guests to withdraw the request before the 24 hour window you have to either accept or decline.
Are you aware that if it's an Inquiry rather than a Request, all you have to do is message back? Pre-approval or declining isn't necessary.
And no, you didn't get blocked for posting on this forum. That doesn't happen, unless you are posting spam, or something obscene or discriminatory. What happens is to do with the programming- sometimes when writing a post it "times out" and you get an errror message or the post disappears into cyberspace. It's a good idea to copy your posts before clicking on the Reply button, so you can just quickly paste it back in and try again.
And this is just a discussion forum for hosts and guests. Airbnb customer service doesn't read or respond to posts here.