The type of protection of the US distributor and the local dealerships that Viva appears to be employing will, unfortunately, hurt some used buyers that unknowingly purchased a unit that has ended up in another country/sales region. But, absent some protection, it is almost impossible for brick and mortar dealerships to make a go of it with people shopping all over the world via the internet after using their local dealership as a show/demonstration room (or even making a purchase without auditioning based on the "wisdom" of the internet or reviewers). Distributor/dealer network for demonstrating gear vs. losing dealers and relying on shows or internet hype to promote the products/brand? This mini war between bargain shoppers and protected local distribution unfortunately appears to have created some collateral damage in the used equipment market. There is a tradeoff involved no matter what the policy employed.
As for repairs of Viva gear, their stuff should be quite easy for any competent repair shop to do the repairs. Most tube gear can be repaired easily without having to go back to the manufacturer.