To VAT or Not to VAT? That is the question

I'm not sure that I remember seeing the OP saying that a bid had been made. If a successful bid has been made, I'd suggest invoking the Ebay disputes procedure, as I can't see there to be a valid reason for backing out of contract.

It could indeed. It strikes me as a pretty unorthodox way of operating in any case. Perhaps whoever was doing it *was* breaking ebay rules.

He did, but not explicitly.

He actually said "whenever I get to sell a dearer item, it is usually to [a] business customer who usually says he won't buy unless he gets a VAT Invoice".

If you take this at face value, then there can be no ambiguity, and "usually says" can only mean that they say so after a bid has gone through, as opposed to enquiring before bidding, and then simply not bidding if getting the answer that no such invoice would be forthcoming. Such pre-bidding queries do happen, but how likely this particular type of pre-bidding query is I wouldn't like to guess.

The reason I think this is what it means is that the stated premise "whenever I get to sell" suggests that the selling procedure has been completed. Otherwise he should instead have said "whenever I try to sell". But of course the OP may have been sloppy with his language and trying to scrutinise what he says using too much logic may well be pointless.

Quite so.