Being forced into paying for a ad slot

Scammer's profile link: Won't share it with me.
Explanation of the trade: A guy PMed me about selling a ad banner slot on his site. His site is incredibly small and I wasn't all that interested with the price he gave me. I said I would MAYBE give him $30 for it, but other sites were a better option for advertising at the rate he wanted.
Amount scammed: Trying to force me to pay $30.
How they scammed: Threatening to tarnish my reputation on various sites if I don't pay him $30. In my opinion I did not give a clear answer as to whether or not I would buy his ad. I said I would maybe give him $30 for it, but immediately listed other sites I would be more interested in at a similar rate. He won't share his Sythe with me and PMed me out of the blue wanting me to put a ad on a site with 130 members. No one else wants to buy his ad because his site is so small so he thinks my "maybe" is a 100% done official business transaction. I did send him an image of my ad so he can see what it looks like, but still IMO that's not a confirmation of any purchase I'm just showing him what would be posted if I did indeed buy it. The conversation below speaks for itself.
Proof that it's their Discord or Skype: Won't share Sythe account with me I can't confirm.
Discord ID + Unique Discord ID or Skype profile ID & conversation pictures: Juicy#2731 403596449918484500
Screenshot - 93ece722249a28caa902851221d96b7a - Gyazo
Screenshot - 0487f055bd18326decd54c9ac6b17a45 - Gyazo
Screenshot - 6c8da784969c16e4cb2efff1635a643a - Gyazo
Screenshot - cf043a1c1642c5a07fca5dddb97fcd8e - Gyazo
Screenshot - 93b88952e5ba9bd145e8f4e67665e5f4 - Gyazo
Other relevant trade screenshots:N/A

If Sythe staff feel my "maybe" is an official confirmation of me wanting to buy his ad then I have no problems at all with paying. But I think it's clear he's trying to force me into paying $30 for something I said I would "maybe" buy!

 

If you did not give him the money, the spot was not yours and it was entirely his choice to "hold" the spot for you - you are not required to buy anything because you were negotiating a price.