If this is how they act when trying to get your money, how will they be once they have it?
That is a valid thought. FWIW, I would walk away, too. Like you, I don't insist on giving my money to people who don't want my business. You were polite and considerate, and the person who responded to you had three opportunities to respond appropriately and failed to do so. Their loss. Perhaps you should be glad that you found out the truth about them before they took their money.