Good point Cusco.... But the question is who should pay? The story is a very complicated one.
In essence the Filser/Funkwerk transponder was approved against a published EASA standard and as far as I know, still complies with the standard.
The guys who designed built and installed the ground-based kit also have equipment that complies with the appropriate standards. But the two bits of kit still the two sometime have difficulty talking to one another. Something fishy with the standards (that by common consent were not the best written ever) you might think.
Don't be too quick to judge when you don't know all the facts. It could be that Filser/Funkwerk have a good case against the authorities.