No refund.
A) If 'not made in China' was a priority for the seller, they should've/would've asked about it beforehand. But they obviously didn't.
That alone is reason enough to say the sale is final.
To me, it sounds like what,
@lapin said, for some reason they changed their mind and are look for an excuse to get out of the purchase.
B) You've confirmed with the U.S. distributor of Royal Exclusive that where it was made ... and you originally purchased it from a reputable retailer and still have the receipt to prove it.
That also reason enough, unto itself, to say the sale is final.
C) AFIK,
U.S. Customs Country of Origin requirements require that imported items need to be marked with
EITHER the english name of the country of origin
or the phrase "Made In [Country Name]".
So, by displaying the Company name and its address in Germany on the product, the requirement is met ... meaning the they didn't need to apply the specific words "Made In Germany".
In fact, the exceeded the requirement because they not only put the country name on it, but also the exact address where purchasers can contact them.