For some strange reason the thing that troubles me most, is why.
I don't believe the guy is a scammer. He's got too much reputation to lose.
I can't speak for the editor in question, but I thought about this quite a bit at one point to figure out how to avoid being that bad editor, and I concluded that:
(a) some strategies and decisions can leave an editor vulnerable to problems, eg. lack of clear deadlines causing jobs to drag on until enthusiasm is lost, payment in advance limiting the financial incentive to complete and deliver work
(b) when problems do arise, the editor's emotional reaction can worsen the situation, eg. feeling ashamed and wanting to hide from the situation, stress leading to reacting defensively
(c) financial problems can lead to a strong need to bring in new clients' cash rather than do promised work for old clients, while payment in advance may already be spent, meaning it can't be refunded in the case of problems
That's not an excuse for lack of professionalism, but it could well be a series of mistakes and misjudgements rather than an active attempt to scam you.