Personally, I don't feel it's very nice to block outright straight away. I would say something like, 'I'm sorry, but I'm no longer enjoying our bookings and suggest you look for another SP.' If he starts whining, then block.
I forgot to block him on WhatsApp and now he’s moved on to there. He’s probably going to make an AW account just to speak to me next too attached and also made a comment saying I remind him of an ex girlfriend