Mr. David "Smudge,"
I looked up the law regarding EULA, to make sure my facts were straight, and as far as I can see it looks like you CANNOT refuse service to a Customer who has purchased a product of yours. Although, you cannot give support services for something you did not make, you as still required, by LAW, to render services to a purchasers/customers. Or, provide some compensation or RETURN policy for defective or unsatisfactory work. Apparently, this is a global policy for all software developers in the business end of production and distribution.
Finally, I fully intend to buy your product, but lets put all these DRAMAs aside and behave like professionals, render service, let people play with their toys and seek your help, advice, and even provide you with some of their talents.