We do not need to claim GST refund / credits.
But in case of problems with the products and services they’ve sold us, would it be more difficult for us to chase the business if the tax invoice is invalid*? Does it even matter we don’t have a valid tax invoice?
*Invalid because the “invoice” they provided doesn’t say “Tax Invoice,” and it doesn’t show how much GST was paid or that it is GST-free. The word GST doesn’t even appear in it.