I ran into the same VAT issue with a UK based vendor who claimed there was so much paperwork involved that they only refunded VAT on orders over a certain amount and that I'd have to pay the VAT then request a refund afterwards.
I find that very difficult to believe as I can order a £2 box of razor blades from a UK shaving supplies vendor, with the VAT automatically deducted. If there was a heap of paperwork involved, they just wouldn't do that. I think it's a ruse when companies do this as they know a fair percentage of customers will be too lazy to ask for the refund.
To be fair, the razor blade vendor may have and probably did have 100 or more times the transactions Pfeifen Depot has. If that is true, they may be more efficiently set up to handle documentation to deal with VAT. Just speculation on my part but seems possible and even logical.