Thanks for reposting. Sorry about my delayed reply.
Do you see how, as well as the colour striping of the moire, the shirt also has some thin stripes of detail, only in some places, of the shirt texture? I know that's real and everything, but I'm afraid we need to get rid of it as well, because it's likely to cause you problems later, when printing.
The re-processing of the raw file reduced the problem somewhat, but it didn't remove it entirely as I'd hoped. So we'll have to do this in a two-step process.
First you'll duplicate the Background layer, and run Filter>Noise>Despeckle. This should get rid of that thin stripy detail (and will also make lots of other detail in the photo blurry, but don't worry about that for now).
Above that, add this Channel Mixer layer:
R 0, +100, 0, -10
G 0, +100, 0, 0
B 0, +100, 0, +19
Then clip that CM layer to the Despeckled layer beneath it.
Then add a black mask to the Despeckled layer. Then carefully paint onto the shirt (don't include the buttons!).
The end result should be a smooth blue shirt, no texture or moire.