Fangthane
Tuck Frump!
The ad explicitly stated that the sale was dependent upon any given buyer being able to prove that they can legally own monitors at their location? You know that for a fact? I think we need to see a screenshot of the ad, before we can even begin to buy into that contention. This all boils down to a decision that the OP made: not to complete the sale that they'd agreed to. As such, no matter how you try to spin it, he's the one who's chosen to postpone-back out-cancel - whatever you want to call it. I think you're grasping at imaginary straws.the buyer refuses to comply with the terms of the sale?
With the reasonable assumption that what you're stating has no basis in reality, we're left with a situation where the seller changed the terms, ex post facto. Since some of you want to try to make this into a TOS matter; if the buyer wasn't informed, prior to sale, that he'd need to prove that he's properly licensed, this clearly becomes an issue of the seller choosing to change the terms of the sale. If it's the seller who breaches the original contract, he has absolutely no right to keep the deposit. This whole discussion is basically mindless noise, but if you want to try to split hairs, let's at least do a good job of it.
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So, OP, let's see screenshots of the original ad and any subsequent correspondence that supports the idea that proof of licensure was always a prerequisite to the transaction being completed.