When you look at your sale reports you will see that the VAT is applied separately from the price that you have chosen for your product.
If you have bought a product from Fab, you have surely noticed that at checkout the VAT is added to the price (which is the price the seller has chosen) and not subtracted from it.
So, the price (P) that the seller chooses is without VAT, Epic applies the VAT (or other taxes) to the customer who pays P+VAT to Epic. Epic pays back the seller only P - Epic processing fee (12%).
All the VAT and taxes are managed by Epic, not by us sellers.
The only thing Fab does wrong at the moment (while the old Marketplace was doing it right) is that it doesn’t show directly the price including taxes but applies taxes at checkout. This is normal in USA, but incorrect in almost all other countries.
In conclusion, what you see deducted from your sales is not the VAT, it’s the 12% that you have to pay at Epic for their Marketplace service.